Scientific Research of NeuroCreatine

CLINICAL STUDIES ON THE FOLLOWING INGREDIENTS:

Lion's Mane

Lion's Mane Mushroom (Hericium erinaceus): A Neuroprotective Fungus with Antioxidant, Anti-Inflammatory, and Antimicrobial Potential—A Narrative Review

Abstract

This narrative review examines the nutritional and therapeutic potential of Hericium erinaceus (lion's mane mushroom), focusing on its anti-inflammatory, antioxidant, and antimicrobial properties. The authors highlight that the mushroom's bioactive compounds — polysaccharides, terpenoids (hericenones and erinacines), and phenolic compounds — scavenge reactive oxygen species and activate the body's own antioxidant defenses, while also showing activity against bacterial and fungal pathogens, including drug-resistant strains. A central theme is the mushroom's ability to stimulate nerve growth factor (NGF) synthesis, positioning it as a candidate for preventing and managing neurodegenerative diseases such as Alzheimer's and Parkinson's. The authors note that despite encouraging findings, robust clinical validation is still lacking, and they call for larger trials, standardized extraction methods, and pharmacokinetic studies to support its use in evidence-based medicine.

Methods: This is a narrative (not systematic) review. The authors searched PubMed, Scopus, ScienceDirect, Web of Science, and Google Scholar through March 2025, using "Hericium erinaceus" combined with terms such as habitat, chemical composition, cultivation, anti-inflammatory/antioxidant/antimicrobial activity, clinical trials, bioavailability, and blood-brain barrier penetration. Only English-language sources from the last two decades were included. Abstracts were screened for relevance, duplicates removed, and eligible studies were qualitatively synthesized. As a narrative review, no formal registration or systematic protocol (e.g., PRISMA) was used.

Results: The review organizes findings across several domains:

• Taxonomy/cultivation: H. erinaceus is a white-rot, hardwood-colonizing fungus, distinguishable from related Hericium species by its compact shape and spine arrangement. It can be cultivated via log cultivation, sawdust blocks, or liquid fermentation, each differing in yield, cost, and use case.
• Chemical composition: Key bioactive groups include polysaccharides (notably β-glucans with immunomodulatory/antitumor effects), terpenoids (hericenones in the fruiting body, erinacines in the mycelium), phenolic acids (gallic, caffeic, p-coumaric), bioactive proteins (lectins, RIPs, hydrophobins), and ergothioneine, an antioxidant amino acid with specialized cellular uptake.
• Anti-inflammatory activity: Erinacines and hericenones inhibit the phosphorylation of IκBα, preventing NF-κB activation and nuclear translocation, reducing pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) while raising anti-inflammatory IL-10. The compounds also inhibit COX-2 and iNOS pathways and activate the Nrf2 antioxidant pathway. These effects are supported by cell-culture studies (e.g., reduced cytokine release in macrophages and microglia) and animal models (reduced neuroinflammation in Alzheimer's models, improved colitis outcomes, reduced systemic inflammation in obese mice).
• Clinical trials: Human evidence remains limited but includes a randomized, double-blind, placebo-controlled trial in older adults with mild cognitive impairment showing cognitive improvements after 16 weeks of supplementation, with benefits fading after discontinuation. Smaller studies suggest benefit in early Alzheimer's disease, gastritis/gut health, and mood symptoms (anxiety/depression), though sample sizes and durations were limited across the board.
• Bioavailability/BBB penetration: Erinacines, being lipophilic, cross the blood-brain barrier more readily than hydrophilic polysaccharides, supporting their neuroprotective role; nanoparticle and lipid-carrier delivery systems are proposed to improve absorption.
• Antioxidant activity: Demonstrated via DPPH, ABTS, FRAP, ORAC, and TBARS assays; mechanisms include ROS scavenging, upregulation of SOD/catalase/GPx, and inhibition of lipid peroxidation. Comparable potency to vitamin C and tocopherols was reported in some studies.
• Antimicrobial activity: Effective primarily against Gram-positive bacteria (S. aureus including MRSA, B. subtilis, E. faecalis) and select fungi (Candida albicans, Aspergillus flavus), with weaker but notable activity against H. pylori and P. aeruginosa. Mechanisms include membrane disruption, biofilm inhibition, enzyme/metabolic interference, and ROS induction in microbes. Effects are described as predominantly bacteriostatic, with some bactericidal activity reported against Gram-positive species, and potential synergy with conventional antibiotics.
• Calcium-binding/other properties: Possible modulation of calcium signaling and metal-ion (Fe, Cu, Zn) chelation, both relevant to mitochondrial function and neurodegeneration.
• Regulatory status: Generally regarded as safe (GRAS); marketed globally as a dietary supplement rather than a pharmaceutical, with differing regulatory treatment in the EU, US, China, and Japan, and no approved health claims to date.

Conclusion: The authors conclude that while preclinical and in vitro evidence strongly supports H. erinaceus's neuroprotective, antioxidant, anti-inflammatory, and antimicrobial properties, clinical validation in humans remains limited and constrained by small, short-duration studies. They identify lack of standardization in cultivation, extraction, and bioactive compound quantification as a major barrier to reproducibility and regulatory acceptance. The review calls for large-scale clinical trials, standardized formulations, pharmacokinetic characterization, and novel delivery systems (e.g., nanoencapsulation) to fully realize the mushroom's potential as a functional food, nutraceutical, or adjunct therapeutic agent, emphasizing the need for collaboration among researchers, clinicians, and regulators.

Source: Alex Graça Contato, Carlos Adam Conte-Junior. "Lion's Mane Mushroom (Hericium erinaceus): A Neuroprotective Fungus with Antioxidant, Anti-Inflammatory, and Antimicrobial Potential—A Narrative Review." PMCID: PMC12030463; PMID: 40284172.

Lion's Mane Mushroom, Hericium erinaceus (Bull.: Fr.) Pers. Suppresses H2O2-Induced Oxidative Damage and LPS-Induced Inflammation in HT22 Hippocampal Neurons and BV2 Microglia

Abstract

This in vitro study compared hot water (HE-HWA) and ethanolic (HE-ETH) extracts from the basidiocarps (fruiting bodies) of Hericium erinaceus for neuroprotective and anti-inflammatory effects. HE-ETH significantly improved viability of HT22 hippocampal neurons exposed to hydrogen peroxide (H2O2), accompanied by reduced reactive oxygen species (ROS), increased catalase (CAT) activity and glutathione (GSH), improved mitochondrial membrane potential and ATP production, reduced mitochondrial toxicity, lowered Bax gene expression, and reduced nuclear apoptosis. Expression of the Nrf2/HO-1/NQO1 antioxidant pathway genes was not significantly affected. HE-ETH also significantly reduced nitric oxide (NO) levels in LPS-stimulated BV2 microglia, indicating anti-inflammatory activity. The authors conclude HE-ETH may be a promising neuroprotective and anti-inflammatory agent in the neuron-glia environment.

Methods: Fresh H. erinaceus basidiocarps were freeze-dried and extracted using two methods: hot water extraction (HE-HWA) and 80% ethanol extraction (HE-ETH). Total phenolic content (TPC) and DPPH radical-scavenging activity were measured for both extracts. HT22 mouse hippocampal neurons and BV2 murine microglia cell lines were used as models. Cytotoxicity of both extracts (50–400 µg/mL) was first assessed via MTS assay to rule out toxicity. Neuroprotection was tested by co-incubating HT22 cells with 250 µM H2O2 plus extract, measuring cell viability, intracellular ROS (DCFH-DA staining), mitochondrial membrane potential (TMRE staining), mitochondrial toxicity and ATP levels (Mitochondrial ToxGlo assay), nuclear apoptosis (Hoechst 33258 staining), caspase-3 activity, and qPCR-based gene expression of Bcl-2, Bax, Nrf2, HO-1, and NQO1. Anti-inflammatory activity was assessed in BV2 microglia stimulated with LPS (1 µg/mL) plus extract, measuring nitric oxide (NO) production via Griess reagent. Statistical comparisons used one- or two-way ANOVA with Tukey's test, or Student's t-test for TPC/DPPH, with significance set at p < 0.05.

Results:

• TPC/DPPH: HE-HWA had significantly higher total phenolic content (3.50 ± 0.09 mg/g GAE) than HE-ETH (2.17 ± 0.03 mg/g GAE), but DPPH radical-scavenging activity was comparable between the two (~13.75–13.93%).
• Cytotoxicity: Neither extract (50–400 µg/mL) was toxic to or increased proliferation of BV2 or HT22 cells.
• Anti-inflammatory (BV2/NO): LPS increased NO production roughly 16-fold (5.06 to 83.68 µM); both extracts reduced NO dose-dependently, with HE-ETH more effective than HE-HWA at 100–400 µg/mL, with the strongest effect (38.73 µM) seen at 400 µg/mL HE-ETH.
• Neuroprotection (HT22 viability): H2O2 reduced viability from 100% to 57.23%; HE-ETH restored viability dose-dependently (69.04%, 82.34%, 96.75% at 100/200/400 µg/mL), while HE-HWA showed no protective effect.
• Antioxidant mechanism: HE-ETH (400 µg/mL) reduced H2O2-induced ROS accumulation, increased CAT activity (11.19 to 15.19 nmol/min/mL), and restored GSH content (from a H2O2-induced drop to 81.42% back up to 109.40%).
• Mitochondrial function: HE-ETH partially restored mitochondrial membrane potential (83.50% to 91.42%), reduced mitochondrial toxicity (211.20% to 92.92%), and increased ATP levels (50.74% to 72.01%) in H2O2-treated cells.
• Anti-apoptosis: HE-ETH markedly reduced H2O2-induced apoptotic nuclei (31.63% down to 2.74%), significantly reduced Bax expression, increased the Bcl-2/Bax ratio (non-significantly), and reduced caspase-3 activity (borderline, p = 0.05).
• Nrf2 pathway: HE-ETH did not significantly alter Nrf2, HO-1, or NQO1 gene expression, despite downstream antioxidant effects (CAT, GSH) being significant — suggesting other pathways may be involved.

Conclusion: The ethanolic extract (HE-ETH) of H. erinaceus basidiocarps showed stronger neuroprotective and anti-inflammatory activity than the hot water extract (HE-HWA). Its neuroprotective effects against H2O2-induced damage in hippocampal neurons appear to work through improved antioxidant defenses, better mitochondrial function, and reduced apoptosis, while its anti-inflammatory action was demonstrated for the first time in BV2 microglia via NO suppression. The authors note this is the first study examining basidiocarp extracts (rather than mycelium-derived erinacines) against H2O2-induced neurotoxicity specifically, and they call for further studies to clarify the exact signaling pathways involved (e.g., MAPK/Akt, Nrf2/ARE) and to confirm efficacy in vivo.

Source: Naufal Kushairi, Chia Wei Phan, Vikineswary Sabaratnam, Pamela David, Murali Naidu. "Lion's Mane Mushroom, Hericium erinaceus (Bull.: Fr.) Pers. Suppresses H2O2-Induced Oxidative Damage and LPS-Induced Inflammation in HT22 Hippocampal Neurons and BV2 Microglia." PMCID: PMC6720269; PMID: 31374912.

Prevention of Early Alzheimer's Disease by Erinacine A-Enriched Hericium erinaceus Mycelia: Pilot Double-Blind Placebo-Controlled Study

Abstract

This pilot randomized controlled trial investigated the efficacy and safety of erinacine A-enriched H. erinaceus (EAHE) mycelia capsules (350 mg/capsule, 5 mg/g erinacine A; three capsules/day) in patients with mild Alzheimer's disease (AD) over a 49-week double-blind treatment period, preceded by a 3-week screening phase. After 49 weeks, the placebo group showed a significant decline in Cognitive Abilities Screening Instrument (CASI) score, while the EAHE group showed significant improvement in Mini-Mental State Examination (MMSE) score, with a significant between-group difference in Instrumental Activities of Daily Living (IADL) scores favoring EAHE. The EAHE group also achieved significantly better contrast sensitivity than placebo. Only the placebo group showed significant deterioration in several blood biomarkers (calcium, albumin, apolipoprotein E4, hemoglobin, brain-derived neurotrophic factor) along with elevated alpha1-antichymotrypsin and amyloid-beta 1–40. Diffusion tensor imaging showed signs of less neural disorganization in the EAHE group compared to placebo in specific brain regions. Aside from four dropouts due to abdominal discomfort, nausea, and skin rash, no other adverse events were reported. The authors conclude EAHE is safe, well-tolerated, and may offer neurocognitive benefits in mild AD.

Methods: This was a 1-year, double-blind, randomized, placebo-controlled, fixed-dose pilot trial at Chung Shan Medical University (Taiwan), registered as NCT04065061. EAHE mycelia (containing 5 mg/g erinacine A, verified by HPLC) were grown via submerged liquid fermentation, lyophilized, and encapsulated. Patients over 50 years old with a diagnosis of probable AD (DSM-IV and NINCDS-ADRDA criteria) were eligible. After a 3-week no-drug screening period, participants were randomized to three 350 mg EAHE capsules/day or matching placebo for 49 weeks, with assessments at baseline, weeks 13, 25, and 49. Outcomes included cognitive tests (NPI, CASI, MMSE, IADL), ophthalmic exams (visual acuity and contrast sensitivity), blood biomarkers (calcium, albumin, hemoglobin, homocysteine, SOD, BDNF, DHEAS, α-ACT, APOE4, amyloid-beta), and brain MRI with diffusion tensor imaging (DTI) assessing fiber tracts linked to memory and language. Statistical analysis used the Mann-Whitney U test for between-group comparisons and Wilcoxon signed-rank test for within-group changes, with significance at p < 0.05. A sample size of at least 60 was targeted based on pilot-study power considerations.

Results:

• Participants: Of 68 screened, 49 were randomized and 41 completed the study (20 EAHE, 21 placebo); no significant baseline differences in age, gender, or education.
• Cognition: CASI scores declined significantly in the placebo group from baseline to week 25 (p = 0.043), while showing a marginal improving trend in EAHE (p = 0.058) by week 49. MMSE significantly improved in the EAHE group from baseline to week 49 (21.75 to 23.2, p = 0.035), with no significant change in placebo. IADL scores differed significantly between groups at week 49 (EAHE 6.7 vs. placebo 5.0, p = 0.012). NPI scores were not significantly different within or between groups.
• Ophthalmic outcomes: No significant change in visual acuity. Contrast sensitivity in the left eye was significantly higher in the EAHE group versus placebo at week 49 (p = 0.046); the placebo group's binocular contrast sensitivity significantly declined over time (p = 0.033).
• Blood biomarkers: EAHE group showed significant improvement in homocysteine (decreased) at weeks 25 and 49. The placebo group alone showed significant negative changes in calcium, albumin, hemoglobin, and BDNF. Both groups showed significant decreases in SOD and APOE4 and increases in α-ACT and amyloid-beta, but these trends were comparatively more favorable in the EAHE group.
• MRI/DTI: Total fiber counts decreased less in the EAHE group than placebo, though the between-group difference wasn't significant (p = 0.715). ADC in the arcuate fasciculus (dominant hemisphere) significantly increased only in placebo (suggesting more disorganization), while ADC in the parahippocampal cingulum significantly decreased only in EAHE (suggesting better-organized structure).
• Safety: Four subjects (3 EAHE, 1 placebo) dropped out due to adverse effects (abdominal discomfort, nausea, skin rash); overall adverse event incidence was 8.2% over 49 weeks, with no other safety concerns reported.

Conclusion: The authors conclude that 49 weeks of EAHE mycelia supplementation was associated with better cognitive outcomes (higher CASI, MMSE, and IADL scores) and improved contrast sensitivity compared to placebo in patients with mild AD, alongside more favorable blood biomarker trends and less structural brain deterioration on MRI. EAHE was safe and well-tolerated. However, as a pilot study, the authors emphasize that larger trials are needed to confirm efficacy and clarify the underlying mechanism of action before broader clinical application.

Source: I-Chen Li, Han-Hsin Chang, Chuan-Han Lin, Wan-Ping Chen, Tsung-Han Lu, Li-Ya Lee, Yu-Wen Chen, Yen-Po Chen, Chin-Chu Chen, David Pei-Cheng Lin. "Prevention of Early Alzheimer's Disease by Erinacine A-Enriched Hericium erinaceus Mycelia: Pilot Double-Blind Placebo-Controlled Study."

Erinacine A-Enriched Hericium erinaceus Mycelium Produces Antidepressant-Like Effects through Modulating BDNF/PI3K/Akt/GSK-3β Signaling in Mice

Abstract

Antidepressant-like effects of ethanolic extract of Hericium erinaceus (HE) mycelium enriched in erinacine A on depressive mice challenged by repeated restraint stress (RS) were examined. HE at 100, 200 or 400 mg/kg body weight/day was orally given to mice for four weeks. After two weeks of HE administration, all mice except the control group went through with 14 days of RS protocol. Stressed mice exhibited various behavioral alterations, such as extending immobility time in the tail suspension test (TST) and forced swimming test (FST), and increasing the number of entries in open arm (POAE) and the time spent in the open arm (PTOA). Moreover, the levels of norepinephrine (NE), dopamine (DA) and serotonin (5-HT) were decreased in the stressed mice, while the levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α were increased. These changes were significantly inverted by the administration of HE, especially at the dose of 200 or 400 mg/kg body weight/day. Additionally, HE was shown to activate the BDNF/TrkB/PI3K/Akt/GSK-3β pathways and block the NF-κB signals in mice. Taken together, erinacine A-enriched HE mycelium could reverse the depressive-like behavior caused by RS and was accompanied by the modulation of monoamine neurotransmitters as well as pro-inflammatory cytokines, and regulation of BDNF pathways. Therefore, erinacine A-enriched HE mycelium could be an attractive agent for the treatment of depressive disorders.

Source: Chiu CH, Chyau CC, Chen CC, Lee LY, Chen WP, Liu JL, Lin WH, Mong MC. "Erinacine A-Enriched Hericium erinaceus Mycelium Produces Antidepressant-Like Effects through Modulating BDNF/PI3K/Akt/GSK-3β Signaling in Mice." Int J Mol Sci. 2018 Jan 24;19(2):341. doi: 10.3390/ijms19020341. PMID: 29364170; PMCID: PMC5855563.

Hericium erinaceus Extract Reduces Anxiety and Depressive Behaviors by Promoting Hippocampal Neurogenesis in the Adult Mouse Brain

Abstract

Versatile biological activities of Hericium erinaceus (HE) have been reported in many brain diseases. However, roles of HE in major psychiatric disorders such as depression and anxiety remain to be investigated. Therefore, we evaluated whether HE could reduce anxiety and depressive behaviors in the adult mouse and its underlying mechanisms. Male C57BL/6 mice were administered HE (20 or 60 mg/kg, p.o.) or saline once a day for 4 weeks. Open field and tail suspension tests were performed 30 min after the last administration of HE, followed by forced swim test 2 days later. We found that chronic administration of HE showed anxiolytic and antidepressant-like effects. To elucidate possible mechanisms, proliferative activity of the hippocampal progenitor cells was assessed by immunohistochemistry of proliferating cell nuclear antigen (PCNA) and Ki67. Moreover, to evaluate neuronal survival in the dentate gyrus, 5-bromo-2'-deoxyuridine (BrdU) (120 mg/kg, i.p.) was given at the first day of HE administration, followed by isolation of the brains 4 weeks later. HE (60 mg/kg) increased the number of PCNA- and Ki67-positive cells in the subgranular zone of the hippocampus, indicating increased proliferation of hippocampal progenitors. In addition, BrdU- and BrdU/NeuN-positive cells in the dentate gyrus were significantly increased when treated with HE (60 mg/kg) compared with the saline-treated group, demonstrating enhanced neurogenesis by HE treatment. Taken together, the results indicate that chronic HE administration can exert anxiolytic and antidepressant-like effects, possibly by enhancing adult hippocampal neurogenesis.

Source: Ryu S, Kim HG, Kim JY, Kim SY, Cho KO. "Hericium erinaceus Extract Reduces Anxiety and Depressive Behaviors by Promoting Hippocampal Neurogenesis in the Adult Mouse Brain." J Med Food. 2018 Feb;21(2):174-180. doi: 10.1089/jmf.2017.4006. Epub 2017 Nov 1. PMID: 29091526.

Dietary Supplementation of Hericium erinaceus Increases Mossy Fiber-CA3 Hippocampal Neurotransmission and Recognition Memory in Wild-Type Mice

Abstract

This study examined whether dietary supplementation with Hericium erinaceus (Hr) affects cognition and hippocampal neurotransmission in healthy (non-pathological) wild-type mice, an area not previously investigated since prior research focused on impaired/diseased models. After two months of oral Hr supplementation, mice showed significant improvements in novel object recognition and increased exploratory behavior in behavioral tests. In hippocampal slices, Hr-supplemented mice showed increased spontaneous and evoked excitatory synaptic currents at the mossy fiber-CA3 synapse. The authors conclude that H. erinaceus produces a general boosting effect on neuronal function even under healthy, non-pathological conditions.

Methods: One-month-old male wild-type C57BL-6J mice were divided into two groups: a control group fed a 5% dextrin supplement (dx mice) and a treatment group fed a 5% "Micotherapy Hericium" supplement (Hr mice, containing both mycelium and fruiting body extract in a 4:1 ratio) for two months. After supplementation, behavioral testing included: (1) the emergence test, measuring exploratory/anxiety-like behavior via latency, frequency, and duration of leaving a safe enclosure for a novel open arena; and (2) the novel object recognition (NOR) task, assessing recognition memory by comparing exploration of a familiar versus novel object. Following behavioral testing, hippocampal slices were prepared from the same mice for whole-cell patch-clamp electrophysiology in CA3 pyramidal neurons, examining spontaneous excitatory postsynaptic currents (sEPSCs) and evoked excitatory postsynaptic currents (EPSCs) at the mossy fiber-CA3 synapse, including paired-pulse facilitation (PPF) to assess presynaptic neurotransmitter release dynamics. Statistical analysis used two-way repeated-measures ANOVA (behavioral data) and Student's t-test (electrophysiology), with significance set at p < 0.05.

Results:

• Emergence test: Hr mice showed significantly more complete exits (9.5 vs. 4.1, p < 0.001), spent more time exploring the novel environment (129.6 vs. 59.2 seconds, p < 0.01), and had shorter latency before first exit (13.1 vs. 31.7 seconds, p < 0.05) compared to dx mice — indicating increased novelty-seeking and reduced anxiety-like behavior.
• Novel object recognition: Hr mice showed significantly more approaches to the novel object (18.9 vs. 13.9, p < 0.05) and longer total duration of approaches (65.4 vs. 45.4 seconds, p < 0.05) compared to dx mice, along with shorter latency to first approach and shorter average latency between approaches. No significant differences were found between groups in behavior toward the familiar object. The novelty discrimination index was higher in Hr mice (0.35) than dx mice (0.15), indicating stronger preference for novelty.
• Spontaneous synaptic currents: The frequency of monoquantal mossy fiber-CA3 spontaneous events was significantly higher in Hr mice (0.13 Hz) than dx mice (0.05 Hz, p < 0.01), while CA3-CA3 recurrent events were unchanged. Overall spontaneous activity was significantly higher in Hr mice (1.79 Hz vs. 1.32 Hz, p < 0.001).
• Evoked synaptic currents: Hr mice showed significantly higher EPSC amplitude (187.9 pA vs. 85.9 pA, p < 0.001) and significantly lower stimulation failure rates than dx mice.
• Paired-pulse facilitation: The paired-pulse ratio was significantly lower in Hr mice (1.2) than dx mice (1.9, p < 0.001), consistent with increased neurotransmitter release probability.
• Cell properties: Input resistance, membrane capacitance, and series resistance of recorded neurons did not differ significantly between groups, indicating the synaptic differences were not due to basic cell health/recording artifacts.

Conclusion: The authors conclude that two months of H. erinaceus dietary supplementation enhances novelty-seeking behavior and recognition memory in healthy wild-type mice, and that this behavioral improvement is paralleled by increased glutamatergic neurotransmission specifically at the mossy fiber-CA3 hippocampal synapse (increased spontaneous/evoked current amplitude and frequency, reduced failure rate, reduced paired-pulse facilitation). They interpret these electrophysiological changes as consistent with increased adult hippocampal neurogenesis in the dentate gyrus, potentially mediated by NGF signaling, though they note further studies are needed to confirm the underlying molecular mechanism. The authors frame this as the first evidence that H. erinaceus can boost neuronal function even in non-pathological, healthy conditions, suggesting potential relevance for future studies in healthy humans.

Source: Federico Brandalise, Valentina Cesaroni, Andrej Gregori, Margherita Repetti, Chiara Romano, Germano Orrù, Laura Botta, Carolina Girometta, Maria Lidia Guglielminetti, Elena Savino, Paola Rossi. "Dietary Supplementation of Hericium erinaceus Increases Mossy Fiber-CA3 Hippocampal Neurotransmission and Recognition Memory in Wild-Type Mice." PMCID: PMC5237458; PMID: 28115973.

The Acute and Chronic Effects of Lion's Mane Mushroom Supplementation on Cognitive Function, Stress and Mood in Young Adults: A Double-Blind, Parallel Groups, Pilot Study

Abstract

This pilot study examined both the acute (single-dose) and chronic (28-day) effects of Hericium erinaceus supplementation on cognitive function and mood in healthy young adults — a population not previously studied, since prior research focused mostly on cognitively compromised or older cohorts. Using a randomized, double-blind, placebo-controlled, parallel-groups design, 41 healthy adults aged 18–45 received either 1.8 g/day of lion's mane or placebo. A single dose led to significantly quicker performance on the Stroop task at 60 minutes post-dose (p = 0.005). After 28 days, there was a trend toward reduced subjective stress (p = 0.051). The authors describe these findings as tentative, given the small sample size and presence of some null or unexpected negative results, but suggest the trial offers a promising direction for further research.

Methods: This was a randomized, double-blind, placebo-controlled, parallel-groups pilot trial conducted at Northumbria University's Brain, Performance and Nutrition Research Centre between April–July 2023. Forty-three healthy adults (ages 18–45, mean 26.35 years; no chronic disease, BMI 18.5–35) were recruited and randomized; 41 completed the chronic-phase analysis. Participants took three capsules daily, containing either placebo (microcrystalline cellulose) or 600 mg lion's mane extract each (1.8 g/day total; SO-DSX1®, Sempera Organics). Compliance was monitored via diary and pill counts (96% average adherence). Cognitive testing used the COMPASS computerized battery, covering attention, executive function, working memory, and episodic memory (via tasks such as word recall, numeric working memory, choice reaction time, Stroop task, peg-and-ball, and delayed word recognition). Mood and stress were assessed via Stress Visual Analogue Scales (S-VAS), Visual Analogue Mood Scales (VAMS), and the Perceived Stress Scale (PSS). Testing occurred at baseline and 60 minutes post-dose on both Day 1 (acute effects) and Day 29 (after 28 days of supplementation, chronic effects), with statistical analysis via two-way ANOVA (treatment × timepoint), followed by planned comparisons only for outcomes with significant ANOVA results.

Results:

• Acute effects (Day 1): A significant treatment × timepoint interaction was found for Stroop task speed (p = 0.027), with lion's mane participants responding significantly faster post-dose (688.05 ms) than at baseline (737.70 ms; p = 0.005). However, immediate word recall accuracy significantly worsened post-dose in the lion's mane group (p = 0.007/0.013), and the placebo group made fewer errors on this task post-dose (p = 0.020/0.002). A significant interaction was also found for the episodic memory composite score, but planned comparisons showed no significant between-group differences at either timepoint.
• Chronic effects (Day 29): A trend-level main effect of treatment was found for Stress VAS scores (p = 0.051), with the lion's mane group reporting significantly lower stress (33.02) than placebo (42.53) on Day 29 (p = 0.033), and a trend toward reduced stress compared to their own Day 1 scores (p = 0.055). No significant difference was found on the Perceived Stress Scale. A significant interaction was found for delayed word recall accuracy, but driven by the placebo group recalling significantly more words at Day 29 than Day 1 (p < 0.001) — not by any improvement in the lion's mane group.
• No significant treatment effects were found on any other individual cognitive task or on the global accuracy/speed composite scores.

Conclusion: The authors tentatively conclude that H. erinaceus may improve speed of performance on a specific cognitive task and may reduce subjective stress with chronic use in healthy young adults — novel findings, since most prior cognitive benefits of lion's mane had been observed only in older or cognitively impaired populations. However, they emphasize that several results were null or even mildly negative (e.g., worse immediate recall after acute dosing), and that the trial was likely underpowered given its small sample size and a cognitively healthy population already near peak performance, making subtle effects hard to detect. The authors call for larger trials, potentially using more cognitively demanding tasks and additional post-dose timepoints, to confirm and clarify these preliminary findings.

Source: Sarah Docherty, Faye L. Doughty, Ellen F. Smith. "The Acute and Chronic Effects of Lion's Mane Mushroom Supplementation on Cognitive Function, Stress and Mood in Young Adults: A Double-Blind, Parallel Groups, Pilot Study." Nutrients. PMCID: PMC10675414; PMID: 38004235.

Ashwagandha

Ashwagandha (Withania somnifera)—Current Research on the Health-Promoting Activities: A Narrative Review

Abstract

This narrative review summarizes recent research on the health benefits of Ashwagandha (Withania somnifera), also known as winter cherry, a plant long used in Ayurvedic medicine. The authors cover its reported neuroprotective, sedative, and adaptogenic effects, as well as anti-inflammatory, antimicrobial, cardioprotective, antidiabetic, anticancer, and reproductive effects. The review aims to provide a comprehensive overview of current evidence on Ashwagandha's potential uses alongside known safety concerns and contraindications.

Methods: This is a narrative review (not a systematic review or meta-analysis), synthesizing findings from preclinical (in vitro and animal) studies and clinical trials across a wide range of health domains. No formal search strategy, database list, or inclusion/exclusion criteria are reported; the authors instead organize evidence thematically by health condition/biological system (e.g., neurodegenerative disease, inflammation, infertility, cancer, sleep, anxiety, muscle strength), citing primary studies for each.

Results: Findings are organized by therapeutic area:

• Active compounds: Key bioactive constituents include witanolides (e.g., withaferin A, withanolide A), alkaloids, and flavonoids, primarily derived from the root.
• Neuroprotective/anti-neurodegenerative effects: In Alzheimer's disease models, Ashwagandha and its components (e.g., withaferin A, withanolide A) reduced amyloid-beta aggregation, tau accumulation, neuroinflammation (via NF-κB), and oxidative stress, with withanolide A shown to cross the blood-brain barrier and reduce ischemic brain damage in mice. In Parkinson's disease models, extracts reduced lipid peroxidation, boosted antioxidant enzymes, and improved motor function in rodents. In Huntington's disease models, extracts and withaferin A improved biochemical and motor parameters and extended survival in mice.
• Psychiatric conditions: In OCD and alcohol withdrawal models, extracts reduced compulsive behaviors and withdrawal anxiety in rodents, comparable to standard treatments. In anxiety disorders, clinical trials reported reductions in Hamilton Anxiety Rating Scale and Perceived Stress Scale scores, reduced cortisol, and support as an SSRI adjunct in generalized anxiety disorder.
• Anti-inflammatory/immunomodulatory effects: Preclinical studies showed inhibition of NF-κB and MAPK pathways, reduced pro-inflammatory cytokines (IL-6, TNF-α, IL-1β), and benefits in lupus and arthritis models; a clinical RCT showed increased natural killer cell activity versus placebo.
• Antibacterial/antifungal properties: Demonstrated in vitro activity against MRSA, Enterococcus spp., various Gram-negative bacteria, oral cavity Streptococcus species, Candida albicans, and antiparasitic activity against Leishmania donovani and malaria in mice.
• Infertility/sexual function: Clinical studies in men with oligospermia or normozoospermia reported increased sperm count, motility, and improved hormone profiles; trials in women reported improved sexual arousal and function versus placebo.
• Anticancer effects: In vitro/in vivo studies showed withaferin A and related compounds induced apoptosis and reduced proliferation in breast, melanoma, glioblastoma, and lung cancer models, with some evidence of protective effects against radiation-induced organ damage.
• Antidiabetic activity: Mostly preclinical evidence of blood-glucose-lowering effects; only one older clinical study (2000) showed a direct glycemic effect, though other trials showed improvements in lipid profile, body weight, and blood pressure.
• Cardioprotective properties: Animal studies showed reduced markers of myocardial necrosis and ischemic damage, with low-dose withaferin A showing cardioprotection via AMPK activation (higher doses were ineffective).
• Sleep disorders: Multiple randomized controlled trials reported improved sleep quality, sleep efficiency, and reduced time to fall asleep, including in older adults and people with non-restorative sleep.
• Anxiolytic/anti-stress and adaptogenic effects: Clinical trials consistently showed reduced stress and anxiety scores (HAM-A, PSS, DASS-21), with proposed mechanisms involving HPA-axis modulation and reduced cortisol/DHEA-S; adaptogenic effects were also shown in an equine (horse) stress model.
• Hypothyroidism: An 8-week RCT in subclinical hypothyroidism showed significant improvement in TSH, T3, and T4 levels versus placebo.
• Muscle strength: Multiple RCTs in healthy men and athletes showed increased muscle strength, mass, and cardiorespiratory endurance, with reduced exercise-induced muscle damage and cortisol.
• Other: Preliminary in vitro/computational evidence suggests some Ashwagandha-derived compounds may inhibit SARS-CoV-2 protease, though this is described as needing further research.
• Safety: While generally well-tolerated in clinical studies (including dose-escalation and toxicity studies), the review highlights rare but documented cases of hepatotoxicity (liver damage), including case reports requiring treatment cessation or, in one case, liver transplant evaluation.
• Contraindications: The review flags hyperthyroidism, hormone-sensitive prostate cancer, pregnancy, autoimmune diseases, and concurrent use with benzodiazepines/barbiturates or immunosuppressants as situations warranting caution or avoidance, along with potential CYP3A4/CYP2B6 drug interactions.

Conclusion: The authors conclude that Ashwagandha demonstrates a wide range of potentially beneficial effects across neurological, psychiatric, immune, metabolic, reproductive, and musculoskeletal domains, supported by a large body of preclinical evidence and a growing but still limited number of clinical trials. They emphasize that despite promising findings, the precise mechanisms of action remain incompletely understood for most effects, and that further well-designed clinical research is needed to confirm therapeutic efficacy, establish optimal dosing, and clarify long-term safety — particularly given emerging reports of hepatotoxicity and potential drug interactions.

Source: Paulina Mikulska, Marta Malinowska, Miłosz Ignacyk, Paweł Szustowski, Joanna Nowak, Karolina Pesta, Monika Szeląg, Damian Szklanny, Eliza Judasz, Gabriela Kaczmarek, Ovinuchi Prince Ejiohuo, Magdalena Paczkowska-Walendowska, Anna Gościniak, Judyta Cielecka-Piontek. "Ashwagandha (Withania somnifera)—Current Research on the Health-Promoting Activities: A Narrative Review." PMCID: PMC10147008; PMID: 37111543.

Efficacy and Safety of Ashwagandha Root Extract on Cognitive Functions in Healthy, Stressed Adults: A Randomized, Double-Blind, Placebo-Controlled Study

Abstract

This randomized, double-blind, placebo-controlled trial evaluated a sustained-release (SR) Ashwagandha root extract capsule (300 mg, Prolanza™) for effects on cognitive function, stress, sleep quality, and overall well-being in 130 healthy adults (20–55 years) experiencing perceived stress (Perceived Stress Scale score 14–24). Participants took one capsule daily (Ashwagandha SR or placebo) for 90 days. Of 130 randomized, 125 completed the study. Using the CANTAB battery, the Ashwagandha SR group showed significantly improved recall memory and reduced pattern-recall errors compared to placebo at day 90. The Ashwagandha SR group also showed significantly lower PSS-10 stress scores, lower serum cortisol, better sleep quality (PSQI), and higher happiness scores (OHQ) than placebo. No adverse events were reported. The authors conclude this sustained-release formulation improved memory, well-being, and sleep quality while reducing stress, and was safe and well-tolerated.

Methods: This was a 90-day, prospective, randomized, double-blind, placebo-controlled, parallel-group trial conducted at two centers in India (December 2019–May 2020), registered with the Clinical Trials Registry-India (CTRI/2019/11/021990). Eligible participants were healthy, cognitively sound adults (ages 20–55, BMI 18–29 kg/m²) with PSS scores of 14–24, confirmed cognitively sound via the Montreal Cognitive Assessment. Exclusions included pregnancy/lactation, postmenopausal status, significant comorbidities, substance dependence, or use of other supplements. Participants were randomized to one daily capsule of Ashwagandha SR (300 mg, containing ≥15 mg total withanolides by HPLC) or matching placebo for 90 days, with visits at screening, baseline (day 1), interim (day 45), and final (day 90). The primary endpoint was change in cognitive function measured by the CANTAB battery (Motor Screening, Paired Associates Learning, Reaction Time, Rapid Visual Information Processing, Spatial Working Memory). Secondary outcomes included PSS-10, serum cortisol (9–11 am), Oxford Happiness Questionnaire (OHQ), Pittsburgh Sleep Quality Index (PSQI), and serum BDNF. Safety was assessed via adverse events and lab values (CBC, ALT, AST, creatinine). Sample size (128 subjects) was powered at 80% to detect a moderate effect size (Cohen's d = 0.5) at α = 0.05. Statistical analysis used ANOVA for within-group changes and ANCOVA (adjusting for baseline) for between-group comparisons, with significance set at p < 0.05.

Results:

• Participants: 130 randomized (65 per group); 125 completed and were analyzed (modified intention-to-treat, >80% compliance).
• CANTAB (cognition): In the Ashwagandha SR group, Paired Associates Learning First Attempt Memory Score significantly improved (10.8 to 12.9, p < 0.05), while the placebo group showed a nonsignificant decline. At visit 4, Ashwagandha SR scored significantly better than placebo for recall memory (12.9 vs. 10.1, p < 0.05) and total errors (17.5 vs. 27.7, p < 0.05). Rapid Visual Information Processing A-prime score was also significantly higher in the Ashwagandha SR group (0.87 vs. 0.83, p < 0.05). Other CANTAB measures (reaction time, motor screening, spatial working memory) showed no significant between-group differences.
• PSS-10 (stress): Significantly decreased in the Ashwagandha SR group (19.5 to 13.0, p < 0.0001) but not in placebo (19.4 to 18.7, p = 0.4955); between-group difference at visit 4 was significant (p < 0.0001), with a large effect size (Cohen's d = 1.55 vs. 0.18 for placebo).
• Serum cortisol: Decreased significantly in both groups, but significantly more so in the Ashwagandha SR group at visit 4 (p = 0.0443).
• OHQ (happiness): Significantly increased in Ashwagandha SR (3.93 to 4.39, p = 0.0003) while significantly decreasing in placebo (3.91 to 3.44); between-group difference was significant (p < 0.0001).
• PSQI (sleep quality): Significantly improved in Ashwagandha SR (4.6 to 2.5, p < 0.0001) but not significantly in placebo (p = 0.08); between-group difference significant (p < 0.0001).
• Serum BDNF: No significant difference between groups at visit 4 (p = 0.7407).
• Safety: No adverse events reported; no abnormal changes in CBC, AST, ALT, or creatinine in either group; five subjects withdrew voluntarily (unrelated to safety) during COVID-19 lockdown.

Conclusion: The authors conclude that this is the first clinical study to assess a sustained-release Ashwagandha formulation, and that 90 days of once-daily Ashwagandha SR capsule use improved objective measures of memory and attention, reduced perceived stress and serum cortisol, and improved sleep quality and psychological well-being compared to placebo, with a favorable safety profile and no adverse events. They highlight the once-daily dosing (versus twice-daily in prior smaller studies) and improved bioavailability of the SR formulation as potential advantages for compliance. The authors note that the study coincided with the COVID-19 pandemic lockdown period, which may have amplified background stress levels in participants, and they call for larger and longer trials across more diverse populations to confirm generalizability.

Source: Kumarpillai Gopukumar, Shefali Thanawala, Venkateswarlu Somepalli, T. S. Sathyanaryana Rao, Vijaya Bhaskar Thamatam, Sanjaya Chauhan. "Efficacy and Safety of Ashwagandha Root Extract on Cognitive Functions in Healthy, Stressed Adults: A Randomized, Double-Blind, Placebo-Controlled Study." PMCID: PMC8632422; PMID: 34858513. CTRI Registration No.: CTRI/2019/11/021990.

Effects of Acute Ashwagandha Ingestion on Cognitive Function

Abstract

This study investigated whether a single (acute) dose of ashwagandha extract affects executive function in healthy adults, an area not previously studied since prior research focused on chronic supplementation. Thirteen healthy volunteers completed a randomized, double-blind, placebo-controlled, crossover trial in which they ingested either 400 mg of ashwagandha extract (NooGandha®) or placebo, then completed cognitive tests (Berg-Wisconsin Card Sorting Task, Go/No-Go, Sternberg Task, Psychomotor Vigilance Task) hourly for 6 hours, before repeating the experiment with the alternate treatment after a 4-day washout. Acute ashwagandha ingestion improved Sternberg Task-measured working memory, particularly at higher cognitive load (6-letter length) and at 3 and 6 hours post-dose. On the Psychomotor Vigilance Task, ashwagandha helped sustain attention and reaction times over time, resisting the mental fatigue seen with placebo. On the Berg-Wisconsin Card Sorting Task, there was some evidence of improved rule-shifting ability, though this appeared driven by baseline differences rather than true treatment effects. On the Go/No-Go test, ashwagandha produced faster (but not more accurate) responses than placebo. The authors conclude that acute 400 mg ashwagandha supplementation improved selected measures of executive function, sustained attention, and short-term/working memory.

Methods: This was a randomized, double-blind, placebo-controlled, crossover, counterbalanced trial (registered as ISRCTN16835354) approved by Texas A&M University's IRB. Fifteen healthy adults (18–59 years, no cognitive deficits, chronic disease, or relevant medication use) were randomized using a balanced Latin Square design; 13 completed all study procedures. Participants fasted 8 hours and limited caffeine/stimulants for 48 hours before each session, then completed four baseline cognitive tests: the Berg-Wisconsin Card Sorting Test (BCST; reasoning, attention shifting, impulsivity), Go/No-Go (GNG; sustained attention, response control), Sternberg Task Test (STT; working memory, cognitive control), and Psychomotor Vigilance Task Test (PVTT; sustained attention, reaction time). Participants then ingested one capsule of either 400 mg placebo (rice flour) or 400 mg liposomal ashwagandha extract, repeating the cognitive battery hourly for 6 hours. After a 4–7 day washout, participants completed the protocol again with the alternate treatment. Side effects were monitored via questionnaire. Statistical analysis used General Linear Model repeated-measures statistics with body weight as a covariate, Wilks' Lambda and Greenhouse-Geisser corrections, Fisher's LSD post hoc tests, and Sidak-adjusted 95% confidence intervals for baseline-change comparisons; significance was set at p ≤ 0.05, with trends noted at p = 0.05–0.10. Effect sizes were assessed via partial eta-squared.

Results:

• BCST: No significant overall treatment × time interaction (p = 0.495), though medium effect sizes were seen for correct responses and errors; ashwagandha showed 1% more correct responses than placebo on average, but baseline-adjusted change-from-baseline analysis suggested this difference was likely due to baseline variation rather than a true treatment effect.
• GNG: No significant overall interaction (p = 0.375), but response time increased (worsened) over time with placebo while being better maintained with ashwagandha, suggesting reduced mental fatigue; accuracy was not improved by ashwagandha (both treatments showed declining accuracy over time).
• STT (working memory): No significant overall interaction (p = 0.857), but medium effect sizes were found for specific conditions, particularly at the highest letter length (6) and present/absent reaction times; ashwagandha better maintained reaction times compared to placebo as task difficulty increased, especially at 3 and 6 hours post-dose.
• PVTT (sustained attention): No significant overall interaction (p = 0.81), but average reaction time worsened over trials with placebo while being better maintained with ashwagandha, suggesting better-sustained vigilance and resistance to mental fatigue.
• Safety: No side effects were reported by participants following either treatment.

Conclusion: The authors conclude that this is the first clinical evidence that a single, acute dose of ashwagandha (400 mg) can improve specific aspects of cognitive performance in healthy young adults — particularly working memory under higher cognitive load and sustained attention/resistance to mental fatigue — even though most formal statistical interactions did not reach significance, with the supportive evidence coming mainly from effect sizes and baseline-adjusted change analyses. They note this builds on, but is distinct from, prior research focused on chronic (multi-week) ashwagandha supplementation, and they call for further research to confirm these effects, including examination of individual variability and potential sex/age-related differences in response.

Source: Dante Xing, Choongsung Yoo, Drew Gonzalez, Victoria Jenkins, Kay Nottingham, Broderick Dickerson, Megan Leonard, Joungbo Ko, Mark Faries, Wesley Kephart, Martin Purpura, Ralf Jäger, Ryan Sowinski, Christopher J. Rasmussen, Richard B. Kreider. "Effects of Acute Ashwagandha Ingestion on Cognitive Function." PMCID: PMC9565281; PMID: 36231152. ISRCTN Registration No.: ISRCTN16835354.

Magnesium

Magnesium and the Brain: A Focus on Neuroinflammation and Neurodegeneration

Abstract

This narrative review examines the role of magnesium (Mg) in brain health, with a focus on its relationship to neuroinflammation and neurodegenerative diseases. The authors describe how magnesium supports nerve signal transmission, ionic homeostasis, and blood-brain barrier (BBB) integrity, and how magnesium deficiency contributes to systemic low-grade inflammation — a common feature underlying most neurodegenerative disorders. The review synthesizes evidence linking disrupted magnesium balance to multiple sclerosis, Alzheimer's disease, and Parkinson's disease, covering mechanisms from neurotransmitter regulation to BBB protection and inflammatory signaling.

Methods: This is a narrative review based on a literature search of PubMed, MEDLINE, and Google Scholar covering publications from 2000 to the present (no specific end date given). No formal systematic search strategy, screening process, or quality assessment criteria are described; evidence is synthesized thematically across mechanistic, preclinical, and clinical studies.

Results: Findings are organized by topic:

• Magnesium's normal role in the brain: Mg acts as a natural calcium antagonist, regulating calcium channels and intracellular calcium release; it is a GABA-A receptor agonist (contributing to anxiolytic/hypnotic effects) and inhibits NMDA receptor overactivation at resting membrane potential, preventing excitotoxic neuronal death. Mg also protects BBB integrity, supports brain-derived neurotrophic factor (BDNF) expression (important for neuroplasticity and memory), and helps counteract oxidative stress.
• Magnesium and neuroinflammation: Mg deficiency promotes neuroinflammation by upregulating inflammation-related genes, activating microglia, and increasing inflammatory mediators including substance P, nitric oxide, prostaglandins, reactive oxygen species, and pro-inflammatory cytokines (TNF-α, IL-1, IL-6) via NF-κB activation. Conversely, Mg administration in various models reduced LPS-induced cytokine release, promoted protective microglial polarization, reduced cerebral edema, and decreased risk of cerebral palsy in preterm neonates following maternal Mg treatment. Mg deficiency also disrupts NMDA receptor regulation, leading to calcium-driven excitotoxicity, and impairs BBB integrity, amplifying neuroinflammatory processes.
• Magnesium and Alzheimer's disease: Reduced brain and circulating Mg levels have been observed in Alzheimer's patients, with a meta-analysis of 21 studies confirming significantly lower circulating Mg compared to healthy controls. Higher dietary Mg intake is inversely associated with cognitive impairment risk. In animal models, Mg supplementation reduced neuroinflammation, decreased amyloid-beta deposition (by favoring α- over β-secretase cleavage), reduced tau phosphorylation, and improved learning and memory. The review also highlights a potential mechanistic link between magnesium deficiency, type 2 diabetes, and Alzheimer's risk via hyperglycemia/hyperinsulinemia-driven amyloid accumulation.
• Magnesium and Parkinson's disease: Lower Mg levels have been found in cerebrospinal fluid and postmortem brain tissue of Parkinson's patients compared to controls. Proposed protective mechanisms include reduced oxidative stress, reduced NMDA receptor overactivity, increased BDNF (supporting dopaminergic neuron survival), and inhibition of α-synuclein aggregation. A Japanese case-control study found higher dietary Mg intake was associated with reduced Parkinson's disease risk. Genetic findings (mutations in the Mg-transporter SLC41A1) and TRPM7 channel dysregulation are also implicated in disease susceptibility.
• Magnesium and multiple sclerosis: Given Mg's anti-inflammatory and calcium-antagonist properties, a protective role is biologically plausible; Mg/vitamin D co-supplementation was associated with fewer disease exacerbations in one trial, though findings on serum Mg levels in MS patients are mixed, with a recent meta-analysis finding no significant difference between patients and healthy controls.
• Unresolved questions: The review highlights open issues including Mg's potential role in cellular senescence/aging, circadian regulation, gut-brain axis effects (via intestinal barrier integrity and microbiota), and the need for more clinical research on which Mg salts most effectively cross the BBB.

Conclusion: The authors conclude that there is substantial evidence supporting a role for magnesium in modulating neuroinflammation and potentially slowing the progression of certain neurodegenerative diseases. They suggest that ensuring adequate, personalized dietary magnesium intake could serve as a preventive measure, while magnesium supplementation might serve as a useful adjunct therapy in neurodegenerative disease management. They call for further clinical research, particularly to identify optimal magnesium formulations for BBB penetration and to clarify magnesium's role in related mechanisms such as cellular senescence and the gut-brain axis.

Source: Jeanette A. M. Maier, Laura Locatelli, Giorgia Fedele, Alessandra Cazzaniga, André Mazur. "Magnesium and the Brain: A Focus on Neuroinflammation and Neurodegeneration." PMCID: PMC9820677; PMID: 36613667.

The Role of Magnesium Therapy in Learning and Memory

Abstract

This book chapter reviews the literature on magnesium's (Mg²⁺) role in cognitive function in both the healthy and the injured/diseased brain, combining published research with original data from the author's laboratory. The chapter examines magnesium's effects on learning and memory in rodent models, including studies on dietary deficiency, direct magnesium administration, and magnesium therapy following traumatic brain injury (TBI) and focal brain lesions, as well as limited human evidence.

Methods: This is a narrative literature review combined with presentation of the author's own laboratory data, rather than a systematic review or meta-analysis. The author summarizes prior published studies and reports original rodent experiments using standard cognitive assessment paradigms, primarily the Morris water maze (MWM, testing reference and working memory via escape latency to a submerged platform), the Barnes spatial maze (a dry analog of the MWM), and operant conditioning chambers (fixed-ratio reinforcement schedules). Experimental designs included: (1) systemic MgCl2 injections (1 or 2 mmol/kg, i.p.) given prior to learning task acquisition in intact rats; (2) 14 days of dietary magnesium deficiency followed by cognitive testing after return to a normal diet; (3) MgCl2 or saline administered after bilateral anterior medial cortex (bAMC) focal lesions, with repeated dosing over 72 hours; and (4) MgCl2 or saline administered after cortical contusion injury (CCI), both bilateral and unilateral models, at various post-injury timepoints. Statistical comparisons (where reported) used standard inferential tests with significance set at p < 0.05.

Results:

• Mg²⁺ administration before learning (intact rats): Daily MgCl2 injections (especially the 2 mmol/kg dose) given before MWM training impaired reference memory acquisition, with significantly longer escape latencies than saline-treated controls by the last two testing days (p < 0.01) — suggesting a transient amnesic effect, consistent with magnesium's NMDA receptor-antagonist properties.
• Dietary Mg²⁺ deficiency: 14 days of a magnesium-deficient diet (followed by return to normal diet before testing) significantly impaired initial acquisition of a reference memory task (p < 0.05), impaired working memory task acquisition (p < 0.05), and reduced operant bar-pressing performance (p < 0.05) — indicating that even temporary magnesium deficiency can produce lasting learning impairments.
• Magnesium-L-threonate (MgT): Noted (citing other researchers' work) to raise cerebrospinal fluid magnesium levels more effectively than other forms (e.g., MgCl2) and to enhance various forms of learning/memory in rodents, including in aged animals, via effects on hippocampal synaptic plasticity.
• Mg²⁺ therapy after focal cortical lesions (bAMC): MgCl2 did not significantly improve reference memory acquisition overall, but did significantly improve working memory performance (especially at the 2 mmol/kg dose, on early testing days) and reduced trials needed to reach criterion on a spatial delayed matching-to-sample task at the higher dose.
• Mg²⁺ therapy after traumatic brain injury (CCI): In a bilateral CCI model, MgCl2 significantly improved reference memory acquisition but not working memory. In a unilateral CCI model, a single MgCl2 dose (1 mmol/kg) given 1 hour post-injury significantly improved both reference and working memory, with working memory performance in treated rats becoming indistinguishable from sham (uninjured) controls.
• Findings from other research groups (reviewed): Results across the literature on Mg²⁺ therapy after brain injury were mixed — some studies showed reduced memory loss after fluid percussion injury, while others found no improvement in reference memory despite reduced hippocampal cell loss, suggesting that structural preservation doesn't always translate to functional cognitive improvement.

Conclusion: The author concludes that magnesium status and magnesium therapy have significant, though task- and dose-dependent, effects on cognitive performance in rodents: magnesium given before learning tasks can impair acquisition (likely via NMDA receptor antagonism), while magnesium deficiency itself impairs learning, and magnesium therapy after brain injury can improve cognitive recovery on certain tasks. The author proposes several possible mechanisms, including correction of injury-induced magnesium depletion, prevention of NMDA receptor-mediated excitotoxicity, reduction of cerebral edema (via aquaporin-4 effects), reduced expression of cell-death-associated genes (e.g., p53), and inhibition of lipid peroxidation. The chapter concludes that further research is warranted, including exploration of magnesium as a co-therapy alongside other nutrients, given evidence that magnesium deficiency is common in humans and may impair cognitive performance.

Source: Michael R. Hoane. "The Role of Magnesium Therapy in Learning and Memory."

Magnesium and Cognitive Health in Adults: A Systematic Review and Meta-Analysis

Abstract

This systematic review and meta-analysis examined associations between various forms of magnesium (Mg) — supplements, dietary intake, and biomarkers — and cognitive outcomes in adults, drawing on evidence from randomized controlled trials (RCTs) and cohort studies. The authors searched PubMed, Embase, PsycINFO, and the Cochrane Central Register of Controlled Trials through May 3, 2024, identifying 3 RCTs and 12 cohort studies. Evidence from RCTs was insufficient to draw firm conclusions on Mg supplements. Cohort data on dietary Mg showed inconsistent dose-response relationships with high heterogeneity, but serum Mg showed a consistent U-shaped association with all-cause dementia and cognitive impairment across studies, with an apparent optimal concentration around 0.85 mmol/L. This nonlinear relationship was confirmed in both meta-regression (p-quadratic = 0.003) and categorical meta-analysis: serum Mg below 0.75 mmol/L carried 43% higher risk (HR = 1.43), and above 0.95 mmol/L carried 30% higher risk (HR = 1.30), compared to the 0.85 mmol/L reference. The authors call for more RCT and cohort evidence, particularly studies using repeated Mg biomarker measurements and accounting for factors like the calcium-to-magnesium intake ratio.

Methods: This was a systematic review and meta-analysis conducted per PRISMA guidelines and preregistered in PROSPERO (CRD42023423663). Databases searched were PubMed, Embase, PsycINFO, and Cochrane CENTRAL (via Ovid) through May 3, 2024, supplemented by manual reference-list searches and a clinical trial registry search. Eligible studies included human participants aged ≥18, with magnesium (supplement, dietary, or biomarker) as exposure and cognitive function/disorder as outcome; studies were excluded if not peer-reviewed original research, non-English, or involving populations with conditions substantially affecting Mg/cognition (e.g., dialysis, TBI, ICU patients). Two reviewers independently screened abstracts and full texts, extracted data, and assessed risk of bias (Cochrane RoB2 tool for RCTs; Newcastle-Ottawa Scale for cohorts). Statistical synthesis used three random-effects models where appropriate: (1) linear dose-response meta-regression, (2) nonlinear (quadratic) meta-regression, and (3) categorical meta-analysis using Mg levels based on existing reference intervals/recommendations (Estimated Average Requirement for dietary Mg; 0.75–0.95 mmol/L reference interval for serum Mg, with risk estimates harmonized to a common 0.85 mmol/L referent using the Hamling method). Heterogeneity was assessed via Cochran's Q and I². Evidence strength was graded using GRADE criteria. Meta-analysis was not performed for RCTs due to the small number of trials (n=3) and high population heterogeneity.

Results:

• RCTs (n=3): One trial in breast cancer patients found 12 weeks of Mg-L-threonate (91.8 mg Mg/day) did not improve cognitive function versus placebo (high risk of bias due to missing data). A second trial nested in a colorectal cancer prevention study found personalized Mg glycinate dosing (mean 216.5 mg/day, targeting a calcium:Mg ratio of 2.3) significantly improved MoCA scores after 12 weeks in adults over 65 (Mg: +2.3 vs. placebo: +0.5, p=0.01), partly explained by reduced APOE gene methylation (low risk of bias). A third trial in patients with compensated liver cirrhosis found 520 mg/day magnesium oxide for 8 weeks improved long-term memory scores versus placebo (4.17 vs. 2.75, p=0.031), though rated high risk of bias due to incomplete outcome reporting.
• Dietary Mg and dementia (6 cohort studies): Results were inconsistent — no association was found in UK Biobank (161,376 adults) or WHIMS (6,473 women) cohorts, but two analyses of the Japanese Hisayama Study found higher dietary Mg intake (~180 mg/d) associated with lower dementia risk (HR 0.50–0.61), while the Shanghai Aging Study found higher dietary Mg associated with increased dementia risk, an effect confined to those with a low calcium-to-magnesium intake ratio. Linear dose-response meta-regression across 4 studies found no clear association (HR=0.98, p=0.87), though a nonlinear model suggested a possible U-shape with lowest risk around 240 mg/day (HR=0.76, borderline p=0.077).
• Mg-containing drug (1 cohort study): Prescribed magnesium oxide use was associated with significantly lower risk of all-cause dementia (HR=0.52) and non-vascular dementia (HR=0.20) versus non-use in a Taiwanese insurance-claims cohort, with stronger effects in long-term users, though the study could not account for dietary Mg intake or dosage.
• Serum/plasma Mg and dementia (5 cohort studies): Results were consistent across studies, showing a U-shaped relationship with lowest dementia/cognitive impairment risk at serum Mg around 0.85 mmol/L. Dose-response meta-regression found each 0.1 mmol/L increase in serum Mg associated with 7% lower risk (HR=0.93, p=0.029), though this attenuated in sensitivity analysis (HR=0.97, p=0.098). The categorical meta-analysis confirmed significantly elevated risk both below 0.75 mmol/L (HR=1.43) and above 0.95 mmol/L (HR=1.30) compared to the 0.85 mmol/L reference, with risk also modestly elevated at intermediate off-center values.
• Supporting neuroimaging evidence: Cited studies found higher dietary Mg intake associated with greater gray matter and hippocampal volume in UK Biobank data, and higher serum Mg associated with greater brain volume and fewer infarcts in another cohort.

Conclusion: The authors conclude, with moderate confidence, that serum magnesium shows a U-shaped association with dementia and cognitive impairment risk, with an apparent optimal level around 0.85 mmol/L — both low and high serum magnesium appear to carry increased risk. Evidence for dietary magnesium intake was graded as low confidence due to inconsistent findings and lack of a clear dose-response pattern, while evidence on magnesium supplements from RCTs remains insufficient due to the small number of trials. They highlight the calcium-to-magnesium intake ratio as a possible explanation for inconsistent dietary findings and call for future cohort studies to use repeated magnesium biomarker measurements, account for both dietary and supplemental sources, and consider the calcium:magnesium ratio, alongside more and larger RCTs to clarify causal effects.

Source: Fan Chen, Jifan Wang, Yijie Cheng, Ruogu Li, Yifei Wang, Yutong Chen, Tammy Scott, Katherine L. Tucker. "Magnesium and Cognitive Health in Adults: A Systematic Review and Meta-Analysis." Advances in Nutrition. PROSPERO Registration: CRD42023423663.

Vitamin B6

The Effect of Vitamin B6 on Cognition

Abstract

Background: Micronutrient status can affect cognitive function at all ages. Vitamin deficiencies could influence memory function and might contribute to age-associated cognitive impairment and dementia. Vitamin B6, comprising three chemically distinct compounds pyridoxal, pyridoxamine, and pyridoxine, is involved in the regulation of mental function and mood. Vitamin B6 is also an essential homocysteine re-methylation cofactor, and deficiency is associated with increase in blood homocysteine levels. Homocysteine is a risk factor for cerebrovascular disease and may also have directly toxic effects on neurons of the central nervous system. Neuropsychiatric disorders including seizures, migraine, chronic pain and depression have been linked to vitamin B6 deficiency. Epidemiological studies indicate that poor vitamin B6 status is common among older people. Hyperhomocysteinaemia has been suggested as a cause or mechanism in the development Alzheimer's disease and other forms of dementia. Supplementation with B vitamins including vitamin B6 has been shown to reduce blood homocysteine levels.

Objectives: To assess the efficacy of vitamin B6 supplementation in reducing the risk of developing cognitive impairment by older healthy people, or improving cognitive functioning of people with cognitive decline and dementia, whether or not vitamin B6 deficiency has been diagnosed.

Main results: No trials of vitamin B6 involving people with cognitive impairment or dementia were found. The two trials included in the review (Bryan 2002; Deijen 1992) used a double-blind, randomized, placebo-controlled design and involved 109 healthy older people. One trial restricted enrolment to women and the other to men. Vitamin B6 supplementation and healthy older women: Bryan 2002 enrolled 211 healthy women from various age groups into a 5-week study. The trial was of multifactorial design with folic acid, vitamin B12, vitamin B6 and placebo in its four arms. Twelve healthy women aged 65 to 92 years received 75 mg vitamin B6 orally per day and were compared with 21 healthy women who were allocated to placebo. No statistically significant benefits from vitamin B6 on mood or cognition were observed. Vitamin B6 supplementation and healthy older men: Deijen 1992 recruited 76 healthy men aged 70 to 79 years. They were divided into 38 matched pairs, one member of each pair randomly allocated to 20 mg of vitamin B6 (pyridoxine hydrochloride) per day for 12 weeks the other to placebo. No statistically significant differences between treatment and placebo were found in their effects on cognition or mood. Effect of vitamin B6 supplementation on vitamin B6 status: Deijen 1992 reported that 20 mg of pyridoxine hydrochloride per day for 12 weeks increased blood vitamin B6 activity as assessed as by plasma pyridoxal-5'-phosphate (WMD 238, 95%CI 211.58 to 264.42, P<0.00001) and erythrocyte enzyme asparate aminotransferase (WMD 0.43, 95%CI 0.30 to 0.56, P<0.00001). Effect of vitamin B6 supplementation on blood homocysteine concentration: Neither of the included trials measured homocysteine levels. Drop-outs: All participants allocated to vitamin B6 or placebo completed the trial protocol. Adverse Events: No adverse effects were reported. Effect of vitamin B6 on carer burden, care costs and institutionalization rate: We found no trials in which these outcomes were assessed.

Conclusion: This review found no evidence for short-term benefit from vitamin B6 in improving mood (depression, fatigue and tension symptoms) or cognitive functions. For the older people included in one of the two trials included in the review, oral vitamin B6 supplements improved biochemical indices of vitamin B6 status, but potential effects on blood homocysteine levels were not assessed in either study. This review found evidence that there is scope for increasing some biochemical indices of vitamin B6 status among older people. More randomized controlled trials are needed to explore possible benefits from vitamin B6 supplementation for healthy older people and those with cognitively impairment or dementia.

Source: Malouf R, Grimley Evans J. "The Effect of Vitamin B6 on Cognition." Cochrane Database Syst Rev. 2003;(4):CD004393. doi: 10.1002/14651858.CD004393. PMID: 14584010.

Vitamin B6, B9, and B12 Intakes and Cognitive Performance in Elders: National Health and Nutrition Examination Survey, 2011–2014

Abstract

This cross-sectional study examined whether dietary intake of vitamins B6, B9, and B12 was associated with low cognitive performance (LCP) in elderly adults, using data from 2,421 participants in the NHANES 2011–2014 database. Cognitive performance was assessed via the CERAD word learning/recall test, the Animal Fluency (AF) test, and the Digit Symbol Substitution Test (DSST), with the lowest-scoring 25th percentile classified as LCP. Compared to inadequate intake, adequate vitamin B6 intake (≥1.7 mg/day) was associated with a 31.7% lower risk of LCP on the DSST. Adequate B9 intake (≥400 mcg/day) was associated with 31.2%, 33.8%, and 46.5% lower LCP risk on the CERAD, AF, and DSST tests, respectively. Adequate B12 intake (≥2.4 mcg/day) was associated with 30.5%, 21.5%, and 33.3% lower LCP risk on the same three tests. These associations varied across sex, race, and age subgroups. The authors conclude that adequate dietary B9 and B12 intake is significantly associated with better cognitive performance across memory, verbal fluency, processing speed, attention, and working memory domains in older adults.

Methods: This was a cross-sectional analysis of NHANES 2011–2012 and 2013–2014 cycle data (the only cycles assessing cognition in both questionnaire and exam settings), including 2,421 participants aged over 60 after exclusions for missing covariate data. Cognitive performance was measured via three validated tests: CERAD (immediate/delayed word recall), AF (categorical verbal fluency, naming animals in 1 minute), and DSST (processing speed/attention/working memory, symbol-matching task). Participants scoring in the lowest 25th percentile on each test were classified as LCP; cutoffs were 5 (CERAD), 13 (AF), and 35 (DSST). Dietary B-vitamin intake was assessed via 24-hour dietary recall (USDA Automated Multiple-Pass Method) and dichotomized at the Recommended Dietary Allowance (RDA): B6 at 1.7 mg/day, B9 at 400 mcg/day, B12 at 2.4 mcg/day. Covariates included age, sex, race, education, poverty-income ratio, alcohol use, diabetes, hypertension, and cardiovascular conditions (heart failure, coronary heart disease, angina, heart attack, stroke). Statistical analysis used univariate and multivariate logistic regression (crude model; Model 1 adjusted for age/sex; Model 2 fully adjusted for additional covariates specific to each cognitive test), incorporating NHANES sample weights, with subgroup analyses by sex, race, and age group. Significance was set at p < 0.05.

Results:

• Baseline characteristics: The LCP group (across all three tests) was older, had higher rates of hypertension, heart failure, heart attack, and stroke, and had a higher proportion of inadequate B9 intake compared to the normal cognitive performance (NCP) group.
• CERAD test (memory): After full adjustment, vitamin B6 was not significantly associated with LCP (p = 0.659). Adequate B9 intake was associated with 31.2% lower LCP odds (OR 0.688, 95% CI 0.507–0.934, p = 0.018), and adequate B12 intake with a similar reduction (OR 0.695, 95% CI 0.522–0.924, p = 0.014).
• AF test (verbal fluency): B6 was not significantly associated with LCP (p = 0.214). Adequate B9 intake was associated with 33.8% lower LCP odds (OR 0.662, p = 0.043), and adequate B12 intake with 21.5% lower odds (OR 0.785, p = 0.036).
• DSST test (processing speed/attention/working memory): All three vitamins showed significant associations. Adequate B6 intake was associated with 31.7% lower LCP odds (OR 0.683, p < 0.001), adequate B9 with 46.5% lower odds (OR 0.535, p = 0.003), and adequate B12 with 33.3% lower odds (OR 0.667, p = 0.002).
• Subgroup analyses: Associations varied by age, sex, and race. For example, B9 and B12 associations with lower LCP risk were generally strongest and most consistent among adults aged 60–69, males, and non-Hispanic White participants, while associations were often non-significant among Hispanic or other racial subgroups (likely due to smaller subgroup sizes).
• Overall pattern: B9 and B12 intake showed the most consistent associations with better cognitive performance across all three tests, while B6 was significantly associated with cognitive performance specifically on the DSST (processing speed, attention, working memory) but not the CERAD or AF tests.

Conclusion: The authors conclude that adequate dietary intake of vitamins B9 and B12 is strongly and consistently associated with lower odds of low cognitive performance across memory, verbal fluency, and processing speed/attention/working memory domains in older US adults, with roughly 30% reductions in LCP odds across tests. Vitamin B6 intake showed a more domain-specific association, linked only to better performance on the DSST. The authors note that these associations varied meaningfully by age, sex, and race, and discuss several plausible biological mechanisms (e.g., B6's role in NMDA receptor function and BDNF expression; B12's role in myelin synthesis and acetylcholine production). They acknowledge that, due to the cross-sectional design, causality cannot be established, and call for larger, longitudinal, and multi-center studies to confirm these associations and clarify underlying mechanisms.

Source: Hui Xu, Shanshan Wang, Feng Gao, Caihong Li. "Vitamin B6, B9, and B12 Intakes and Cognitive Performance in Elders: National Health and Nutrition Examination Survey, 2011–2014." PMCID: PMC8962758; PMID: 35359912. Funding: Joint Project of the Medical Science and Technology of Henan Province (2018020264).

Vitamin B6: A New Approach to Lowering Anxiety, and Depression?

Abstract

This letter to the editor discusses and summarizes a University of Reading study examining the effects of high-dose vitamin B6 supplementation on anxiety and depression in young adults, in the context of the broader public health burden of anxiety and mood disorders. The authors describe how B6 supplementation was linked to increased GABA activity and reduced self-reported anxiety/depression symptoms, and they argue that vitamin B6 may represent a useful nutrition-based adjunct or alternative to conventional anxiolytic medications, while cautioning that the evidence is still preliminary.

Methods: This piece summarizes findings from a cited randomized trial (University of Reading research group, published in Human Psychopharmacology: Clinical and Experimental) in which 478 participants with self-reported depression and/or anxiety were randomized to vitamin B6, vitamin B12, or placebo for over a month. That cited study assessed effects on GABA-related processes and used the Mood and Feelings Questionnaire (MFQ) and the Screen for Adult Anxiety Related Disorders (SCAARED) to evaluate anxiety and depressive symptoms before and after treatment. The current article also references a separate cross-sectional study comparing dietary B6 intake between anxious/depressed and healthy individuals, and a separate 8-week Phase IV randomized controlled trial examining combined magnesium and vitamin B6 supplementation in stressed/anxious individuals with low magnesium levels.

Results: Based on the cited University of Reading study: vitamin B6 supplementation produced a statistically significant reduction in self-reported anxiety and depression symptoms compared to placebo, accompanied by higher GABA levels in the B6 group. The vitamin B12 group showed only a minor improvement in anxiety and depression relative to placebo. The cited cross-sectional study found that average dietary vitamin B6 intake was significantly lower in anxious and depressed individuals compared to healthy controls. The cited magnesium + B6 trial found that combined supplementation was associated with greater daily physical activity and a significant reduction in stress among healthy individuals with severe stress/anxiety and low magnesium levels.

Conclusion: The authors conclude that vitamin B6 may help relieve symptoms of anxiety and depression and could be a valuable dietary addition, particularly given that conventional treatments like benzodiazepines carry risks such as dependence, rebound anxiety, memory impairment, and discontinuation syndrome. However, they emphasize that the supporting research is still in early stages, that the observed effect of B6 on anxiety was relatively modest compared to what might be expected from pharmaceutical treatment, and that further research is needed to identify and combine nutrition-based interventions — potentially alongside therapies such as Cognitive Behavioral Therapy — to improve mental well-being.

Source: Duaa Durrani, Rahma Idrees, Hiba Idrees, Aayat Ellahi. "Vitamin B6: A New Approach to Lowering Anxiety, and Depression?" PMCID: PMC9577631; PMID: 36268413.

Vitamin B12

Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression

Abstract

This systematic review and meta-analysis assessed the effects of vitamin B12 supplementation — alone or as part of a B-complex with folic acid (±B6) — on cognitive function, depressive symptoms, and idiopathic fatigue in patients without advanced neurological disorders or overt B12 deficiency. The authors searched Medline, Embase, PsycInfo, Cochrane Library, and Scopus, identifying 16 RCTs with 6,276 participants. No evidence was found for an effect of B12 alone or B-complex supplementation on any cognitive function subdomain (executive function, memory, global cognition, processing speed), and meta-regression found no significant moderating effect of baseline B12 levels, dose, duration, or population characteristics. No overall effect was found on depression measures. Only one study reported on idiopathic fatigue, precluding meta-analysis. The authors conclude that vitamin B12 supplementation is likely ineffective for improving cognitive function and depressive symptoms in patients without advanced neurological disorders.

Methods: This systematic review followed PRISMA guidelines and was registered with PROSPERO (CRD42019135823). A systematic search of MEDLINE, Embase, PsycINFO, Cochrane Library, and Scopus was conducted in June 2020 (with no date or language restrictions), supplemented by searches of clinical trial registries and manual reference-list screening. Eligible studies were double-blind, placebo-controlled RCTs with ≥20 participants per arm (age ≥18), using a daily defined dose of ≥100 mcg vitamin B12 (oral or intramuscular), examining cognitive function, depression, or fatigue. Studies were excluded if they targeted overt B12 deficiency/neuropathy ("replacement" rather than "supplementation"), advanced neurological disorders (e.g., Alzheimer's, dementia, stroke), major depression/psychotic disorders, highly specialized populations, multivitamins beyond B9/B6, or had high risk of bias. Two reviewers independently screened studies and assessed quality using the Cochrane RoB 2 tool; overall evidence quality was graded using GRADE. Outcomes were standardized into effect sizes (Hedges' g) using three-level random-effects (3LRE) meta-analysis models (to account for non-independent multiple outcomes within studies), with sensitivity analyses using robust variance estimation (RVE) models. Cognitive outcomes were grouped into four subdomains (executive, memory, global, speed). Meta-regression examined moderators (baseline B12 levels, intervention type, treatment duration, bioavailable dose, population characteristics) when ≥10 studies were available per outcome. Publication bias was assessed via funnel plots and Egger's test. Given multiple hypothesis testing, statistical significance was set at p < 0.005.

Results:

• Study selection: From 10,250 initially identified studies, 16 RCTs met inclusion criteria (3 testing B12 alone, 12 testing B-complex, 1 testing both vs. placebo). Twelve trials had low risk of bias; five raised some concerns; one high-risk trial was excluded.
• Cognitive function (12 studies): No significant effect was found for B12 alone or B-complex on any cognitive subdomain. Effect sizes were small and non-significant across executive function (B12 alone: 0.09; B-complex: 0.06), memory (B12 alone: 0.04; B-complex: 0.03), global cognition (B12 alone: 0.02; B-complex: 0.07), and speed (B12 alone: −0.10; B-complex: −0.08). Meta-regression found no significant association between treatment effect and any tested moderator (baseline B12 level, dose, duration, population type).
• Depressive symptoms (6 studies): No significant overall effect of B12 or B-complex supplementation on depression measures (pooled effect size: −0.049, 95% CI −0.146 to 0.047).
• Idiopathic fatigue: Only one study reported on this outcome, precluding meta-analysis; that study found a significant difference favoring placebo at baseline, complicating interpretation of its modestly significant later finding favoring B12.
• Sensitivity analyses: The robust variance estimation model produced similar point estimates to the primary 3LRE model but with wider confidence intervals, supporting the robustness of the null findings.
• Quality/publication bias: Evidence was graded as moderate quality for cognitive subdomains and depression; no funnel plot asymmetry was detected, suggesting no strong evidence of publication bias.

Conclusion: The authors conclude that, based on high-quality evidence, vitamin B12 supplementation (alone or as part of a B-complex) shows no meaningful benefit for cognitive function or depressive symptoms in patients without advanced neurological disorders or overt B12 deficiency — populations that represent the majority of patients for whom B12 is commonly prescribed. They note this contrasts with the continued popularity and high prescription rates of B12 supplementation in patients with normal or undocumented B12 levels, and they raise concern given other observational research linking B12 supplementation to potential risks (e.g., hip fractures, lung cancer, all-cause mortality). Evidence on fatigue remains too sparse to draw conclusions. The authors call for future research focused on long-term supplementation effects (beyond the two-year durations studied so far), idiopathic fatigue specifically, and B12's role in increasingly common meat-free diets, while explicitly cautioning that this review does not address B12 "replacement" in true deficiency states.

Source: Stefan Markun, Isaac Gravestock, Levy Jäger, Thomas Rosemann, Giuseppe Pichierri, Jakob M. Burgstaller. "Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression." PMCID: PMC8000524; PMID: 33809274. PROSPERO Registration: CRD42019135823.

Vitamin B12: A Cornerstone of Cognitive and Metabolic Well-Being in Young Adults

Abstract

This systematic review investigates the relationship between vitamin B12 levels, biochemical markers, electrophysiological parameters, and cognitive functions, with particular attention to the impacts on obesity in young adults. Vitamin B12 plays a critical role in supporting metabolic and neurological health. This review emphasizes the potential risks associated with B12 deficiency, especially for individuals following restrictive diets such as vegetarianism or veganism. Comprehensive searches were conducted across databases, including Web of Science, PubMed, Scopus, and Google Scholar, encompassing research published from January 2010 to February 2024. The selection process focused on original research, review articles, and clinical studies that examined the correlation between serum vitamin B12 levels, biochemical markers such as homocysteine and methylmalonic acid, and cognitive and metabolic outcomes. The review included approximately 80 high-quality studies. Key findings indicate that low vitamin B12 levels are common among obese individuals, contributing to metabolic disturbances such as insulin resistance, increased inflammation, and lipid imbalances, which can further exacerbate obesity. The deficiency is also linked to compromised cognitive performance, including deficits in memory, executive function, and attention, due to impaired nerve conduction and altered neurotransmitter synthesis. This highlights the interconnected nature of B12 deficiency, obesity, and cognitive health, underscoring the need for targeted interventions. Ensuring adequate vitamin B12 intake is essential for maintaining metabolic balance and cognitive function, particularly in populations at risk of deficiency due to dietary restrictions or obesity. The review advocates for the development of tailored dietary guidelines and supplementation strategies to prevent deficiency and its associated health risks. Future research should focus on establishing causal relationships and evaluating effective intervention methods to support metabolic and cognitive health.

Source: Deepanshi Sharma, Amandeep Singh, Yash Prashar. "Vitamin B12: A Cornerstone of Cognitive and Metabolic Well-Being in Young Adults." Obesity Medicine.

Assessment of Vitamin B12 Efficacy on Cognitive Memory Function and Depressive Symptoms: A Systematic Review and Meta-Analysis

Abstract

This systematic review and meta-analysis evaluated the effect of vitamin B12 supplementation on cognitive memory function and depressive symptoms, particularly in participants who may have mild cognitive impairment (MCI). Following Cochrane Handbook and PRISMA guidelines, the author searched PubMed, CENTRAL, Medline, and Ovid through August 31, 2024, including only randomized controlled trials (RCTs). Risk of bias was assessed using the Cochrane ROB2 tool, and meta-analysis was conducted using Jamovi software. From 483 initial records, nine RCTs were included. For cognitive memory function (8 of 9 studies analyzed), the average standardized mean difference was -0.03 (95% CI: -0.07 to 0.01), showing no significant effect (p = 0.1801) and no significant heterogeneity. For depressive symptoms (3 of 9 studies analyzed), the average standardized mean difference was -0.01 (95% CI: -0.0773 to 0.0525), also showing no significant effect (p = 0.708). The author concludes that vitamin B12 complex supplementation has an insignificant effect on cognitive function and depressive symptoms in the general population, though further research is needed to identify conditions under which B12 may be more effective.

Methods: This systematic review followed Cochrane Handbook (v6) guidelines and PRISMA reporting standards. Inclusion criteria: double-blind RCTs; participants with or without MCI, aged >55 years; studies on vitamin B complex effects on cognitive memory and/or depression; English-language publications. Exclusion criteria: patients with neuropathy, advanced neurological conditions, or chronic medical conditions; qualitative-only studies; letters, reviews, editorials, observational/retrospective studies, and abstracts. Four databases (PubMed, CENTRAL, Medline, Ovid) were searched through August 31, 2024, using terms including "B12 vitamin," "cyanocobalamin," "methylcobalamin," "cognitive function," and "cognitive decline," with no geographic, racial, or age constraints, supplemented by reference-list screening. A single independent researcher conducted searches, screening, and full-text review. Extracted data included author, year, population, sample size, age, B-complex dosing/route/frequency, treatment duration, follow-up, and outcomes. Risk of bias was assessed using the Cochrane ROB2 tool (five domains: randomization, deviations from intervention, missing outcome data, outcome measurement, selective reporting), visualized using Robvis. Meta-analysis used standardized mean differences via random-effects models (restricted maximum-likelihood estimator), with heterogeneity assessed via Q-test and I² statistic; significance threshold was p < 0.05.

Results:

• Study selection: From 438 records (8 duplicates removed, 410 excluded by title/abstract, 11 more excluded after full-text review for incomplete outcome reporting, being reviews, or inappropriate populations), 9 RCTs were included, spanning sample sizes of 179–2,919 participants, mean ages 60–82.5 years, B12 doses of 500–1,000 mcg/day (combined with 400 mcg B9, and B6 in some studies), and treatment durations of 24–104 weeks.
• Risk of bias: Low risk across all domains for most studies; two studies raised some concerns regarding deviations from intervention, missing data, outcome measurement, or selective reporting.
• Cognitive memory function (7 studies in final analysis): Standardized mean differences ranged from -0.3026 to 0.1753 (58% negative). The pooled random-effects estimate was -0.03 (95% CI: -0.07 to 0.01, p = 0.1801), with no significant heterogeneity (I² = 20%, p = 0.8175) — indicating no meaningful effect of B12 complex supplementation on memory.
• Depressive symptoms (3 studies): Pooled standardized mean difference was -0.01 (95% CI: -0.0773 to 0.0525, p = 0.708), with no significant heterogeneity (I² = 25%, p = 0.7256) — indicating no meaningful effect on depression.

Conclusion: The author concludes that vitamin B12 complex supplementation shows no significant effect on cognitive memory function or depressive symptoms in the general population studied. However, the discussion notes that this null finding may not generalize to specific subgroups — citing other research suggesting B12 may offer benefits in populations with diagnosed deficiencies, elevated homocysteine levels, or conditions involving oxidative stress/neuroinflammation. The author highlights key limitations, including that all included trials co-administered B9 (folate) and sometimes B6 alongside B12, making it difficult to isolate B12's independent effect, along with inconsistent dosing and outcome measurement tools across studies. The author calls for future research using personalized approaches — assessing baseline B12/homocysteine status and malabsorption risk factors — to identify which patients are most likely to benefit from B12 supplementation, rather than treating it as universally effective.

Source: Hayat Alzahrani. "Assessment of Vitamin B12 Efficacy on Cognitive Memory Function and Depressive Symptoms: A Systematic Review and Meta-Analysis." Cureus. PMCID: PMC11628180; PMID: 39655146.

Vitamin B12 Deficiency and Cognitive Impairment: A Comprehensive Review of Neurological Impact

Abstract

This narrative review synthesizes evidence from human and animal studies on the neurocognitive consequences of vitamin B12 deficiency and evaluates supplementation strategies. The authors describe vitamin B12 as essential for myelin integrity, neurotransmitter synthesis, and homocysteine metabolism, and explain how deficiency disrupts these processes, leading to oxidative stress, vascular damage, and neurodegeneration that worsen cognitive decline. The review emphasizes that B12 deficiency is multifactorial — driven by dietary inadequacy, physiological changes, and environmental factors — and disproportionately affects high-risk groups such as the elderly and vegetarians/vegans. The authors advocate for routine screening, dietary adjustments, and early supplementation, while highlighting emerging biomarkers and neuroimaging techniques as tools for improved diagnosis and intervention.

Methods: This is a narrative review (not a systematic review or meta-analysis) synthesizing evidence from case studies, population-level observational research, animal studies, and clinical trials. No formal systematic search strategy, database list, or inclusion/exclusion criteria are specified; the authors instead organize the review thematically, covering: (1) mechanistic pathways of B12's neurological effects, (2) clinical case study evidence, (3) population-level epidemiological research, (4) B12 metabolism and absorption physiology, (5) risk factors for deficiency, and (6) biomarkers for diagnosing B12-related cognitive decline.

Results: Findings are organized across several domains:

• Mechanisms: B12 (cobalamin) functions via methylation reactions (converting homocysteine to methionine, supporting S-adenosylmethionine/SAMe production essential for neurotransmitter synthesis), myelin synthesis (via methylmalonyl-CoA to succinyl-CoA conversion), neuroprotection/axonal regeneration (e.g., reducing ER-stress-mediated apoptosis and promoting remyelination in traumatic brain injury models), antioxidant/anti-inflammatory activity, and epigenetic regulation via RNA methylation (e.g., m6A methylation affecting neuronal gene expression).
• Clinical case studies: Multiple individual case reports describe patients (ranging from an 8-month-old infant to adults in their 30s–50s) presenting with neurological symptoms (sensory ataxia, paresthesia, motor decline, reduced responsiveness) attributable to confirmed B12 deficiency, several occurring without accompanying anemia or macrocytosis, with symptom improvement following supplementation — illustrating that B12 deficiency can present as an isolated neurological condition.
• Population-level research: Cited studies report associations between low B12 and increased dementia/Alzheimer's risk (e.g., a ~1.5-fold increased risk in one study), though evidence on related questions like chronic proton-pump-inhibitor (PPI) use and dementia risk was mixed across multiple meta-analyses, with some finding significant associations and others finding none. A pediatric study found neurological symptoms in B12-deficient children resolved within a month of supplementation.
• Metabolism: The review details B12's absorption pathway (haptocorrin → intrinsic factor → cubilin-mediated uptake in the terminal ileum → transcobalamin II transport), and explains how disruptions (pernicious anemia, atrophic gastritis, GI diseases, genetic mutations) impair this pathway and lead to deficiency.
• Risk factors: The review catalogs major risk factors including vegetarian/vegan diets, gastrointestinal disorders, certain medications (notably metformin and proton pump inhibitors, with metformin users showing ~19% lower B12 levels on average and PPI use over two years associated with a 65% increased deficiency risk), aging-related gastric atrophy (affecting ~10–15% of those over 60), pernicious anemia, pregnancy, alcoholism, and chronic kidney disease, alongside environmental factors like air pollution and food/water contamination affecting B12-producing gut bacteria.
• Biomarkers: The review evaluates serum B12, holotranscobalamin (holoTC), methylmalonic acid (MMA), and total homocysteine (tHcy) as diagnostic markers, noting that serum B12 alone is an unreliable standalone marker (many people with levels 200–350 pg/mL show functional deficiency via elevated MMA/homocysteine), while holoTC <35 pmol/L and MMA >0.4 µmol/L are presented as more sensitive/specific indicators, with combined biomarker panels offering the highest diagnostic accuracy.
• Supplementation/trial evidence: A summarized table of relevant studies shows mixed results — some observational studies found associations between B12 status and cognitive outcomes (e.g., higher B12 quartiles linked to better cognitive scores in one study), while others (including two cited RCTs with samples of 2,214 and 2,919 patients) found no significant effect of B12 supplementation (500 mcg/day) on global cognition measures (MMSE, TICS-m).

Conclusion: The authors conclude that vitamin B12 plays a critical role in maintaining cognitive health, particularly in older adults and other vulnerable populations, and that deficiency contributes to structural brain changes (myelin degeneration) and biochemical disruption (elevated homocysteine) linked to cognitive decline. They note that while B12 supplementation (particularly methylcobalamin) has shown promise in animal models for reversing neurological damage, human clinical trial results remain mixed, indicating a need for further research. The review emphasizes that environmental and dietary factors compound deficiency risk, and calls for future studies to clarify B12's therapeutic potential for cognitive decline and to better understand interactions between environmental, dietary, and genetic factors in B12 metabolism.

Source: Milind Umekar, Tanvi Premchandani, Amol Tatode, Mohammad Qutub, Neha Raut, Jayshree Taksande, Ujban Md. Hussain. "Vitamin B12 Deficiency and Cognitive Impairment: A Comprehensive Review of Neurological Impact." Brain Disorders.

Creatine

Creatine Prevents the Structural and Functional Damage to Mitochondria in Myogenic, Oxidatively Stressed C2C12 Cells and Restores Their Differentiation Capacity

Abstract

Creatine (Cr) is a nutritional supplement promoting a number of health benefits. Indeed Cr has been shown to be beneficial in disease-induced muscle atrophy, improve rehabilitation, and afford mild antioxidant activity. The beneficial effects are likely to derive from pleiotropic interactions. In accord with this notion, we previously demonstrated that multiple pleiotropic effects, including preservation of mitochondrial damage, account for the capacity of Cr to prevent the differentiation arrest caused by oxidative stress in C2C12 myoblasts. Given the importance of mitochondria in supporting the myogenic process, here we further explored the protective effects of Cr on the structure, function, and networking of these organelles in C2C12 cells differentiating under oxidative stressing conditions; the effects on the energy sensor AMPK, on PGC-1α, which is involved in mitochondrial biogenesis and its downstream effector Tfam were also investigated. Our results indicate that damage to mitochondria is crucial in the differentiation imbalance caused by oxidative stress and that the Cr-prevention of these injuries is invariably associated with the recovery of the normal myogenic capacity. We also found that Cr activates AMPK and induces an upregulation of PGC-1α expression, two events which are likely to contribute to the protection of mitochondrial quality and function.

Source: Barbieri E, Guescini M, Calcabrini C, Vallorani L, Diaz AR, Fimognari C, Canonico B, Luchetti F, Papa S, Battistelli M, Falcieri E, Romanello V, Sandri M, Stocchi V, Ciacci C, Sestili P. "Creatine Prevents the Structural and Functional Damage to Mitochondria in Myogenic, Oxidatively Stressed C2C12 Cells and Restores Their Differentiation Capacity." Oxid Med Cell Longev. 2016;2016:5152029.

Role of Creatine Supplementation in Conditions Involving Mitochondrial Dysfunction: A Narrative Review

Abstract

Creatine monohydrate (CrM) is one of the most widely used nutritional supplements among active individuals and athletes to improve high-intensity exercise performance and training adaptations. However, research suggests that CrM supplementation may also serve as a therapeutic tool in the management of some chronic and traumatic diseases. Creatine supplementation has been reported to improve high-energy phosphate availability as well as have antioxidative, neuroprotective, anti-lactatic, and calcium-homoeostatic effects. These characteristics may have a direct impact on mitochondrion's survival and health particularly during stressful conditions such as ischemia and injury. This narrative review discusses current scientific evidence for use or supplemental CrM as a therapeutic agent during conditions associated with mitochondrial dysfunction. Based on this analysis, it appears that CrM supplementation may have a role in improving cellular bioenergetics in several mitochondrial dysfunction-related diseases, ischemic conditions, and injury pathology and thereby could provide therapeutic benefit in the management of these conditions. However, larger clinical trials are needed to explore these potential therapeutic applications before definitive conclusions can be drawn.

Source: Marshall RP, Droste JN, Giessing J, Kreider RB. "Role of Creatine Supplementation in Conditions Involving Mitochondrial Dysfunction: A Narrative Review." Nutrients. 2022 Jan 26;14(3):529.

Oral Creatine Monohydrate Supplementation Improves Brain Performance: A Double-Blind, Placebo-Controlled, Cross-Over Trial

Abstract

Creatine supplementation is in widespread use to enhance sports-fitness performance, and has been trialled successfully in the treatment of neurological, neuromuscular and atherosclerotic disease. Creatine plays a pivotal role in brain energy homeostasis, being a temporal and spatial buffer for cytosolic and mitochondrial pools of the cellular energy currency, adenosine triphosphate and its regulator, adenosine diphosphate. In this work, we tested the hypothesis that oral creatine supplementation (5 g d(-1) for six weeks) would enhance intelligence test scores and working memory performance in 45 young adult, vegetarian subjects in a double-blind, placebo-controlled, cross-over design. Creatine supplementation had a significant positive effect (p < 0.0001) on both working memory (backward digit span) and intelligence (Raven's Advanced Progressive Matrices), both tasks that require speed of processing. These findings underline a dynamic and significant role of brain energy capacity in influencing brain performance.

Source: Rae C, Digney AL, McEwan SR, Bates TC. "Oral Creatine Monohydrate Supplementation Improves Brain Performance: A Double-Blind, Placebo-Controlled, Cross-Over Trial." Proc Biol Sci. 2003 Oct 22;270(1529):2147-50.

Creatine Supplementation and Cognitive Performance in Elderly Individuals

Abstract

The purpose of this study was to examine the effect of creatine supplementation on the cognitive performance of elderly people. Participants were divided into two groups, which were tested on random number generation, forward and backward number and spatial recall, and long-term memory tasks to establish a baseline level. Group 1 (n = 15) were given 5 g four times a day of placebo for 1 week, followed by the same dosage of creatine for the second week. Group 2 (n = 17) were given placebo both weeks. Participants were retested at the end of each week. Results showed a significant effect of creatine supplementation on all tasks except backward number recall. It was concluded that creatine supplementation aids cognition in the elderly.

Source: McMorris T, Mielcarz G, Harris RC, Swain JP, Howard A. "Creatine Supplementation and Cognitive Performance in Elderly Individuals." Neuropsychol Dev Cogn B Aging Neuropsychol Cogn. 2007 Sep;14(5):517-28.

Effects of Creatine on Mental Fatigue and Cerebral Hemoglobin Oxygenation

Abstract

While the role of creatine in preventing muscle (peripheral) fatigue for high performance athletes is well understood, its biochemical role in prevention of mental (central) fatigue is not. Creatine is abundant in muscles and the brain and after phosphorylation used as an energy source for adenosine triphosphate synthesis. Using double-blind placebo-controlled paradigm, we demonstrated that dietary supplement of creatine (8 g/day for 5 days) reduces mental fatigue when subjects repeatedly perform a simple mathematical calculation. After taking the creatine supplement, task-evoked increase of cerebral oxygenated hemoglobin in the brains of subjects measured by near infrared spectroscopy was significantly reduced, which is compatible with increased oxygen utilization in the brain.

Source: Watanabe A, Kato N, Kato T. "Effects of Creatine on Mental Fatigue and Cerebral Hemoglobin Oxygenation." Neurosci Res. 2002 Apr;42(4):279-85.

Effect of Creatine Supplementation and Sleep Deprivation, with Mild Exercise, on Cognitive and Psychomotor Performance, Mood State, and Plasma Concentrations of Catecholamines and Cortisol

Abstract

Rationale: Sleep deprivation has a negative effect on cognitive and psychomotor performance and mood state, partially due to decreases in creatine levels in the brain. Therefore, creatine supplementation should lessen the negative effects of sleep deprivation.

Objectives: The objective of this study was to examine the effect of creatine supplementation and sleep deprivation, with mild exercise, on cognitive and psychomotor performance, mood state, and plasma concentrations of catecholamines and cortisol.

Method: Subjects were divided into a creatine group (n=10) and a placebo group (n=9). They took 5 g of creatine monohydrate or a placebo, dependent on their group, four times a time a day for 7 days, immediately prior to the experiment. The study was double blind. Subjects undertook tests of random movement generation (RMG), verbal and spatial recall, choice reaction time, static balance and mood state pre-test (0 h), after 6, 12 and 24 h of sleep deprivation, with intermittent exercise. They were tested for plasma concentrations of catecholamines and cortisol at 0 and 24 h.

Results: At 24 h, the creatine group demonstrated significantly less change in performance from 0 h (delta) in RMG, choice reaction time, balance and mood state. There were no significant differences between groups in plasma concentrations of catecholamines and cortisol. Norepinephrine and dopamine concentrations were significantly higher at 24 h than 0 h, but cortisol were lower.

Conclusions: Following 24-h sleep deprivation, creatine supplementation had a positive effect on mood state and tasks that place a heavy stress on the prefrontal cortex.

Source: McMorris T, Harris RC, Swain J, Corbett J, Collard K, Dyson RJ, Dye L, Hodgson C, Draper N. "Effect of Creatine Supplementation and Sleep Deprivation, with Mild Exercise, on Cognitive and Psychomotor Performance, Mood State, and Plasma Concentrations of Catecholamines and Cortisol." Psychopharmacology (Berl). 2006 Mar;185(1):93-103.

Ginkgo Biloba

Ginkgo biloba: A Treasure of Functional Phytochemicals with Multimedicinal Applications

Abstract

This narrative review describes Ginkgo biloba, an ancient plant with a chemically diverse profile of bioactive compounds, and its reported medicinal/pharmacological properties — including anticancer, antidementia, antidiabetic, antiobesity, antilipidemic, antimicrobial, antioxidant, anti-inflammatory, hepatoprotective, antidepressant, antiaging, immunomodulatory, antihypertensive, and neuroprotective effects. The authors describe the plant's chemical constituents, nutraceutical value, toxicity profile, adverse effects, synergistic interactions, and relevant clinical studies. They highlight the plant's antioxidant/free-radical-scavenging properties as central to many of its effects, note that long-term or high-dose use can cause adverse effects and drug interactions, and conclude that while preclinical and clinical evidence supports therapeutic potential across multiple conditions, further research is needed to confirm safety and efficacy.

Methods: This is a narrative review (not a systematic review or meta-analysis), synthesizing evidence from phytochemical analyses, in vitro studies, animal (in vivo) studies, and human clinical trials/RCTs. No formal systematic search strategy, database list, or inclusion/exclusion criteria are reported. The review is organized thematically, covering chemical constituents, nutraceutical composition, bioactive compounds, pharmacological activities by disease/system, commercial uses, synergistic effects, adverse effects, toxicity (in vivo and in vitro), and clinical studies, drawing on both standardized extracts (notably EGb 761) and other Ginkgo-derived preparations.

Results: Key findings organized by category:

• Chemical constituents: G. biloba contains over 110 identified flavonoids, terpenoids (ginkgolides A/B/C/J/M/etc. and bilobalide), alkylphenols/alkylphenolic acids (including toxic ginkgolic acids), carboxylic acids, lignans, proanthocyanidins, polyprenols, and polysaccharides.
• Nutraceutical value: G. biloba seeds are nutrient-dense, containing protein, carbohydrates, vitamins (B1, B2, B3, B6, C), and minerals (potassium, magnesium, phosphorus), and have a long history of culinary use in East Asia.
• Respiratory: Ginkgolide M/B and EGb 761 reduced inflammatory cell aggregation and cytokine production (IL-4, -5, -6, -8, -13, TNF-α) in LPS- and allergy-induced lung injury models.
• Anticancer: GBE and related extracts inhibited tumor cell proliferation, reduced tumor markers, and suppressed angiogenesis-related signaling (Wnt/β-catenin/VEGF) in liver, lung, and gastric cancer models.
• Antidementia: EGb 761 was reported to prevent amyloid toxicity, modulate glutamatergic neurotransmission, and act as a radical scavenger.
• Antidiabetic: Bilobalide and ginkgolide B improved insulin signaling, reduced inflammation, and improved antioxidant enzyme activity in rodent models.
• Antiobesity/antilipidemic: GBE and ginkgolide B/C reduced body weight, hepatic steatosis, and dyslipidemia in high-fat-diet rodent models, partly via PPAR/LXR/FXR and lipase-inhibition pathways.
• Cardiovascular: Ginkgo seed extracts reduced cholesterol and triglycerides while increasing HDL in animal models.
• Antimicrobial: Ginkgolic acids and ginkgolides showed activity against several bacteria (e.g., S. aureus, E. coli, K. pneumoniae) and fungi.
• Antioxidant: Multiple ginkgo components reduced ROS/RNS, MDA, and oxidative markers across various tissue/cell models (neuronal, hepatic, ocular).
• Wound healing/antiaging: GBE reduced oxidative damage in irradiation and frostbite models and showed protective effects on skin fibroblasts.
• Antiplatelet: Ginkgolide B reduced platelet activation markers via Syk/p38 MAPK inhibition.
• Anti-inflammatory: Biflavones (ginkgetin, bilobetin, isoginkgetin) reduced pro-inflammatory cytokines and mediators (NO, TNF-α, IL-6, PGE2, COX-2) across multiple models.
• Hepatoprotective: GBE reduced liver enzyme elevation and oxidative damage in toxin-induced liver injury models.
• Antidepressant: GBE and diterpene ginkgolides reduced depressive-like behaviors in animal models, associated with BDNF modulation and altered neurotransmitter levels.
• Immunomodulatory: Ginkgo polysaccharides enhanced immune cell activity at moderate doses but showed immunosuppressive effects at high doses in a fish model.
• Clinical studies (human): Notable findings include: EGb 761 (240 mg/day) showing benefit over placebo in stabilizing/improving cognition and reducing neuropsychiatric symptoms in dementia patients across multiple trials, with comparable effects to donepezil in one study; GBE (120 mg/day) improving glycemic control in type 2 diabetes patients as adjuvant therapy; GBE improving lipid profile compared to statins in one study; EGb 761 (240 mg/day) reducing tardive dyskinesia symptoms in schizophrenia patients in RCTs; EGb 761 (240–480 mg/day) improving cognition and reducing anxiety in generalized anxiety disorder patients; and GBE showing antidepressant effects in elderly depressed patients.
• Adverse effects/toxicity: G. biloba seeds contain the neurotoxin 4'-O-methylpyridoxine (ginkgotoxin), structurally similar to vitamin B6, which can cause seizures and vitamin B6 deficiency at high intake (documented in case reports). Leaf extracts carry lower but nonzero MPN risk, plus documented concerns about bleeding risk (mixed evidence), drug interactions (e.g., with warfarin, monoamine oxidase inhibitors, antipsychotics), and isolated case reports of arrhythmia and allergic contact dermatitis. In vivo rodent studies found increased liver weight, hepatocellular adenomas, and reduced survival with long-term high-dose administration; in vitro studies found mutagenic activity in bacterial assays at high concentrations.

Conclusion: The authors conclude that G. biloba has been studied extensively in RCTs and consistently shows a generally favorable safety profile along with promising therapeutic effects across a wide range of conditions, particularly cognitive/dementia-related applications. However, they note that inconsistent methodologies, outcome measures, and dosing across studies complicate cross-study comparisons, and call for more standardized, systematic research — including better characterization of dose-response relationships, optimal treatment duration, conditions where Ginkgo is most/least effective, and underlying mechanisms (e.g., mitochondrial effects) that remain underexplored. They frame G. biloba as a promising natural complementary therapy, contingent on clinicians and researchers having a thorough understanding of its pharmacology, dosing, and interaction risks.

Source: Noor-E-Tabassum, Rajib Das, Mashia Subha Lami, Arka Jyoti Chakraborty, Saikat Mitra, Trina Ekawati Tallei, Rinaldi Idroes, Amany Abdel-Rahman Mohamed, Md Jamal Hossain, Kuldeep Dhama, Gomaa Mostafa-Hedeab, Talha Bin Emran. "Ginkgo biloba: A Treasure of Functional Phytochemicals with Multimedicinal Applications." PMCID: PMC8901348; PMID: 35265150.

Ginkgo biloba Extract Improves Cognitive Function and Increases Neurogenesis by Reducing Aβ Pathology in 5×FAD Mice

Abstract

This study tested whether Ginkgo biloba extract (EGb 761) protects against Alzheimer's disease (AD)-related cognitive decline using 5×FAD transgenic mice, an animal model of amyloid-beta (Aβ) pathology. Mice received daily intraperitoneal injections of EGb 761 (0, 10, 20, or 30 mg/kg) for four months, after which learning/memory, hippocampal neurogenesis, Aβ levels, and neuronal morphology were assessed. EGb 761 at 20 and 30 mg/kg ameliorated memory deficits in both spatial (Morris Water Maze) and nonspatial (novel object recognition) memory tasks. EGb 761 treatment also reduced the number of Aβ-positive signals, increased the number of newborn neurons in the dentate gyrus, and increased dendritic branching and spine density compared to untreated 5×FAD mice. The authors conclude that EGb 761 has a protective effect against memory deficits in 5×FAD mice, likely mediated by reduced Aβ pathology and enhanced neurogenesis.

Methods: Four-month-old male 5×FAD transgenic mice (Tg, n=48) and wild-type littermates (WT, n=12) were used, with genotyping confirmed via PCR. Tg mice received daily intraperitoneal injections of EGb 761 at 0, 10, 20, or 30 mg/kg for four months; WT littermates served as negative controls. Mice were divided into three experimental groups: (1) behavioral testing via novel object recognition (NOR, nonspatial memory) and Morris Water Maze (MWM, spatial memory); (2) neurogenesis assessment via BrdU labeling and immunofluorescence, plus Aβ quantification via ELISA (soluble Aβ1-40/Aβ1-42) and immunofluorescence (6E10 antibody) and Thioflavin-S staining (amyloid plaques); and (3) Golgi staining of CA1 hippocampal neurons to assess dendritic morphology (branching, spine density/maturity) via Sholl analysis. Statistical comparisons used one-way ANOVA with LSD post hoc tests; significance was set at p < 0.05.

Results:

• Nonspatial memory (NOR): 5×FAD mice showed significantly less preference for the novel object than controls (p < 0.05), indicating memory impairment. EGb 761-treated groups (10, 20, 30 mg/kg) spent significantly more time exploring the novel object, with the 30 mg/kg group showing the most enhanced preference index.
• Spatial memory (MWM): 5×FAD mice required more time to find the escape platform and showed fewer platform crossings than controls (p < 0.05). Both 20 mg/kg and 30 mg/kg EGb 761 significantly reduced escape latency and increased platform crossings (p < 0.05 for both), and the 30 mg/kg group spent more time in the target quadrant (>25%) compared to untreated 5×FAD mice, indicating improved spatial memory.
• Neurogenesis: BrdU-positive (newborn) cell counts were lower in 5×FAD mice (90.10 ± 25.8) than WT controls (151.9 ± 45.1). EGb 761 treatment at 20 and 30 mg/kg increased BrdU-positive cell counts to levels approaching WT mice. Similarly, doublecortin-positive (DCX+, immature neuron marker) cell counts, reduced in 5×FAD mice, were significantly increased by 30 mg/kg EGb 761 treatment (p < 0.05).
• Aβ pathology: Aβ-positive immunofluorescent signals were significantly increased in 8-month-old Tg mice versus controls, and appeared reduced with EGb 761 treatment. ELISA showed no significant difference in soluble Aβ1-40 across groups, but soluble Aβ1-42 was significantly elevated in Tg mice versus controls (p < 0.05) and was significantly reduced by EGb 761 treatment.
• Amyloid plaques (Thioflavin-S): Plaque-positive signals were significantly increased in Tg mice versus controls (p < 0.05) and were reduced by EGb 761 treatment.
• Dendritic morphology: 5×FAD mice showed significantly fewer dendritic branches near the cell body and reduced basilar dendritic trees compared to controls (p < 0.001/p < 0.05). EGb 761 (30 mg/kg) significantly increased total dendrite length and reversed reductions in dendritic branching and Sholl-analysis intersections (p < 0.05). The proportion of mature dendritic spines, reduced in 5×FAD mice, was also restored toward control levels by EGb 761 treatment.

Conclusion: The authors conclude that long-term (four-month) EGb 761 treatment improves both spatial and nonspatial memory in the 5×FAD mouse model of Alzheimer's disease, and that this cognitive benefit is associated with increased hippocampal neurogenesis (more newborn and immature neurons in the dentate gyrus), reduced soluble Aβ1-42 and amyloid plaque burden, and improved dendritic morphology (branching and mature spine density) in hippocampal neurons. They propose that EGb 761's neuroprotective effects in this model are linked to its ability to reduce Aβ pathology and promote neurogenesis, supporting its potential therapeutic value for neurodegenerative conditions involving impaired neurogenesis, though the precise molecular mechanisms remain to be fully elucidated.

Source: Wei Ge, Chao Ren, Lei Xing, Lina Guan, Caiyi Zhang, Xuwen Sun, Guoping Wang, Haichen Niu, Sen Qun. "Ginkgo biloba Extract Improves Cognitive Function and Increases Neurogenesis by Reducing Aβ Pathology in 5×FAD Mice." PMCID: PMC8014356; PMID: 33841671.

Ginkgo biloba: An Updated Review on Pharmacological, Ethnobotanical, and Phytochemical Studies

Abstract

This narrative review synthesizes 20 years (2003–2023) of literature on the ethnobotanical, phytochemical, and pharmacological aspects of Ginkgo biloba, a "living fossil" plant with a long history of medicinal use. The authors searched PubMed, Embase, Scopus, and Google Scholar without language restriction, and found that G. biloba extracts and isolated compounds (terpenoids, flavonoids, bioflavonoids, organic acids) show beneficial effects across the cerebrovascular/nervous, cardiovascular, endocrine, muscular/skeletal, renal, respiratory, digestive, and immune systems. The authors conclude that while substantial preclinical and clinical evidence exists, further human-controlled trials are needed to robustly establish efficacy and safety.

Methods: This is a narrative review (not a systematic review/meta-analysis). PubMed, Embase, Scopus, and Google Scholar were searched using "Ginkgo biloba" or "ginkgo" combined with terms like "phytochemistry," "ethnobotany," "pharmacology," "nervous system," and "cardiovascular," covering literature from 2003 to October 2023, with no language restriction. No formal inclusion/exclusion criteria, screening process, or quality/risk-of-bias assessment is reported; findings are organized thematically by organ system/disease area, summarizing in vitro, in vivo (animal), and (briefly) clinical evidence in extensive reference tables.

Results: Findings are organized by body system, drawing on a very large number of cited studies:

• Chemistry: Confirms over 100 flavonoids, ginkgolides A–Q, bilobalide, alkylphenols/ginkgolic acids (toxic), phenolic acids, lignans, proanthocyanidins, and polyprenols as key constituents, with standardized extracts (e.g., EGb 761) typically containing 22–27% flavonoid glycosides and 5–7% terpene lactones.
• Nervous system/cerebrovascular: Extensive preclinical evidence shows EGb 761 and isolated compounds (ginkgolide A/B/K, bilobalide, ginkgetin, biginkgosides) provide neuroprotection across many models — cerebral ischemia/reperfusion, hemorrhagic stroke, Alzheimer's disease (reducing Aβ-induced toxicity, oxidative stress, and tau phosphorylation), Parkinson's disease, epilepsy, neuropathic pain, multiple sclerosis, depression, anxiety, and tardive dyskinesia — generally via antioxidant, anti-inflammatory, and anti-apoptotic mechanisms. However, the review notes discrepancies: while some studies suggest cognitive benefit in Alzheimer's/dementia, a cited network meta-analysis found EGb 761 showed no treatment advantage over placebo in mild-to-moderate Alzheimer's disease. A systematic review on ischemic stroke found only small neurological benefit, which needs to be weighed against risks like increased intracranial bleeding and mortality.
• Cardiovascular system: Studies show benefits for ischemia, arrhythmia, atherosclerosis, hypertension, cardiac remodeling, and myocardial infarction via antioxidant, anti-inflammatory, and anti-apoptotic pathways, and via inhibition of platelet aggregation/thrombin activity. However, a cited double-blind trial found G. biloba did not reduce total mortality or cardiovascular death/event rates.
• Endocrine system: Evidence supports benefits for diabetes mellitus (types 1 and 2), obesity, diabetic nephropathy/cataracts, and reproductive system effects (protecting against chemotherapy- and EMR-induced testicular/ovarian damage), generally via antioxidant, anti-inflammatory, and lipid-modulating mechanisms; some weak estrogenic activity was also noted.
• Muscular/skeletal system: Studies show benefit for osteoporosis (via increased osteoblastic differentiation, reduced apoptosis) and osteoarthritis (via reduced cartilage matrix degradation).
• Renal system: Demonstrated renoprotective effects against chemically-induced injury (e.g., cisplatin, CCl4, lead), diabetic nephropathy, hypertension-induced renal injury, and ischemia-reperfusion injury, largely via antioxidant and anti-inflammatory mechanisms.
• Respiratory system: Shown to reduce inflammation in LPS-induced lung injury, asthma, pulmonary fibrosis, and acute lung injury models.
• Gastrointestinal system: Demonstrated benefit for peptic/gastric ulcers, colitis, inflammatory bowel disease, and hepatoprotection against various hepatotoxic insults (paracetamol, cadmium, fluoride, arsenite).
• Immune system/cancer: Extensive preclinical evidence across many cancer types (hepatocellular, gastric, breast, lung, pancreatic, prostate, colorectal, skin/melanoma, multiple myeloma, bladder) shows G. biloba compounds (notably ginkgolic acids, ginkgetin, EGb 761) can induce apoptosis, inhibit proliferation/migration/invasion, and act as chemosensitizers in various in vitro and in vivo cancer models.

Conclusion: The authors conclude that G. biloba contains a rich and well-characterized set of bioactive compounds (terpene lactones and biflavonoids being most pharmacologically significant) responsible for wide-ranging protective effects demonstrated across nearly every major organ system in preclinical research. They emphasize that ginkgolic acids are toxic/allergenic and that standardized extracts should be limited to ≤5 ppm ginkgolic acid content per German regulatory guidance. Despite the breadth of preclinical evidence, the authors state that further studies — particularly robust human clinical trials — are needed to confirm the claimed health benefits of G. biloba and establish stronger evidence for its efficacy and safety in humans.

Source: Maryam Akaberi, Hamed Baharara, Mohammad Sadegh Amiri, Ali Tafazoli Moghadam, Amirhossein Sahebkar, Seyed Ahmad Emami. "Ginkgo biloba: An Updated Review on Pharmacological, Ethnobotanical, and Phytochemical Studies." Pharmacological Research – Modern Chinese Medicine.

Standardized Extract of Ginkgo biloba Enhances Memory Persistence Over Time

Abstract

This study investigated whether post-training treatment with a standardized Ginkgo biloba extract (EGb), with composition similar to EGb 761, modulates the consolidation and long-term persistence of fear memory in rats, an effect not previously characterized by the authors' group. Rats received EGb (250, 500, or 1000 mg/kg), vehicle, or diazepam immediately after conditioned lick suppression training, with memory persistence tested either 2–4 days later (recent long-term memory) or 40–42 days later (remote long-term memory). EGb enhanced memory persistence in a dose- and time-dependent manner: the highest dose (1000 mg/kg) improved both recent and remote fear memory retention without preventing fear extinction, while the lowest dose (250 mg/kg) promoted persistence of the original remote fear memory but interfered with extinction memory formation; the intermediate dose (500 mg/kg) appeared linked to anti-anxiety effects. Phytochemical analysis (UHPLC-HRMS/MS and molecular networking) confirmed the presence of ginkgolides A, B, and D along with flavonoids including quercetin, rutin, and nicotiflorin. The authors conclude this is the first demonstration that EGb modulates both recent and remote fear memory consolidation and persistence, suggesting potential as an adjunct treatment for memory decline or anxiety disorders.

Methods: Adult male Wistar rats were used in a conditioned lick suppression paradigm (a fear-conditioning task measuring suppression of licking behavior in response to a tone previously paired with foot shock). After establishing baseline licking, rats underwent conditioning (tone-shock pairings) and were then treated orally, immediately post-training, with EGb (250, 500, or 1000 mg/kg), vehicle, or diazepam (4 mg/kg, a GABA-A agonist used as a positive/impairment control). Memory was tested across three sessions: a retention test (T1), an extinction training session (T2), and an extinction retention test (T3), conducted either 2–4 days post-training (Experiment 1: recent memory) or 40–42 days post-training (Experiment 2: remote memory). The primary outcome was the suppression ratio (SR), calculated from licking latency before versus during the tone, with SR near 1.0 indicating high fear/suppression and SR ≤0.5 indicating low fear/failure to learn. Latency to lick during pre-CS versus CS periods was also analyzed. The EGb extract was separately characterized using UHPLC-HRMS/MS in positive and negative ion modes, with molecular networking and dereplication performed via the GNPS platform to identify constituent compounds. Statistical analysis used one- or two-way ANOVA with Tukey's post hoc tests, or two-tailed paired t-tests for within-group comparisons, with significance set at p < 0.05.

Results:

• Recent memory (Experiment 1): At T1 (2 days post-training), the 1000 mg/kg EGb group showed a significantly higher suppression ratio than vehicle, 250 mg/kg, and 500 mg/kg groups (p = 0.0060), indicating enhanced recent memory retention. No significant group differences emerged at T2 or T3. Latency analysis showed all groups retained fear memory (higher latency during CS than pre-CS) at T1, with the 1000 mg/kg EGb group showing significantly higher latency than vehicle and 250 mg/kg groups. Notably, diazepam impaired fear memory extinction (sustained high latency at T2), while all EGb doses allowed normal extinction.
• Remote memory (Experiment 2): No significant group differences emerged at T1 or T2 in suppression ratio, but at T3 (42 days post-training), the 250 mg/kg EGb group showed significantly stronger licking suppression than vehicle, diazepam, and 1000 mg/kg groups (p = 0.0007), and the 500 mg/kg group also showed higher suppression than diazepam — suggesting low-dose EGb enhanced original (remote) memory persistence. Latency analysis showed the 1000 mg/kg EGb group had significantly higher latency during CS at T1 (enhanced remote memory), while at T2, the 250 mg/kg group showed signs of impaired extinction (higher latency during CS, unlike other groups), consistent with low-dose EGb preserving the original fear memory against extinction.
• Phytochemical analysis: Dereplication via UHPLC-HRMS/MS and GNPS molecular networking identified ginkgolides A, B, and C, the sesquiterpene bilobalide, and several flavonoid-3-O-glycosides (quercetin-3-O-robinobioside, rutin, nicotiflorin, isoquercitrin, kaempferol derivatives) as major constituents of the EGb extract, consistent with known EGb 761-type compositions.

Conclusion: The authors conclude that this is the first study to show that post-training EGb treatment modulates both recent and remote fear memory consolidation and persistence in a dose- and time-dependent manner: high-dose EGb (1000 mg/kg) enhances both recent and remote memory retention without blocking extinction learning, while low-dose EGb (250 mg/kg) preferentially strengthens persistence of the original remote memory and interferes with extinction. They propose that these effects likely involve modulation of synaptic plasticity-related signaling (e.g., NMDA-GluN2B, GABA-A receptors, BDNF, CREB) within the hippocampus and connected limbic regions (amygdala, prefrontal cortex), and that the identified flavonoid (quercetin, rutin, nicotiflorin) and terpenoid (ginkgolides, bilobalide) constituents of EGb likely underlie its neuroprotective and memory-modulating effects. They suggest EGb may have potential as an adjunct treatment for memory decline or anxiety disorders, pending further mechanistic research.

Source: Andressa Gabriela Soliani, Beatriz Gangale Muratori, Augusto Leonardo dos Santos, Patricia Sartorelli, Suzete Maria Cerutti. "Standardized Extract of Ginkgo biloba Enhances Memory Persistence Over Time." Phytomedicine Plus. Funded by São Paulo State Research Foundation (FAPESP), grant 2016/18039-9.

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