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Lion's mane mushroom

Also called Hericium erinaceus, Yamabushitake, Hou Tou Gu, Monkey head mushroom, Bearded tooth mushroom, Pom pom mushroom. Edible and medicinal mushroom (fungus).

Lion's mane mushroom: erinacine A, a diterpenoid from the mycelium; the mushroom is a mixtureOOOHOHHOO
Lion's mane mushroom: erinacine A, a diterpenoid from the mycelium; the mushroom is a mixture.C25H36O6Structure: PubChem CID 10410568, National Center for Biotechnology Information
Evidence last reviewed Added to the site 18 studies citedEditorial review: NootropicsWork Editorial TeamEducational, not medical advice
On this page
  1. Bottom line
  2. Evidence by outcome
  3. Doses studied
  4. What it is
  5. Safety and interactions
  6. Regulatory status
  7. FAQ
  8. References

Bottom line

Lion's mane (Hericium erinaceus) is an edible mushroom also sold as a supplement [24]. Small trials, several with company ties, found better cognitive screening scores in older adults, mostly with mild cognitive impairment or mild Alzheimer's disease, and mixed, isolated speed effects in healthy young adults [1][2][3][5][6][7]. The idea that it regrows neurons comes from cell and animal studies [17][18].

  • In a 16-week placebo-controlled trial in 30 Japanese adults with mild cognitive impairment, run by a mushroom company researcher, cognitive scale scores rose with lion's mane but fell again within 4 weeks of stopping [1].
  • In healthy young adults, single doses were followed by faster performance on some tasks in two trials, one using product donated by the manufacturer and one part-funded by the extract supplier [5][7], while another single-dose trial, with authors from a company selling lion's mane, and a 4-week trial of 10 g a day found no overall effect [6][8].
  • In a 28-day trial in 84 young women with stress or anxiety, every group improved, including placebo, and the primary anxiety score was lower with a lion's mane and reishi blend than with lion's mane alone; the manufacturer, Sempera Organics, donated the products [10].
  • Nerve growth and neurogenesis findings come from cell and rodent studies [18][17].
  • Reported side effects include abdominal discomfort, nausea and skin rash (in an industry-run trial), and two case reports describe acute respiratory failure and anaphylaxis [3][13][14][24].

New to Lion's mane mushroom? Start with What is lion's mane? A plain-English guide.

Evidence by outcome

OutcomeGradeBasisModifiersRationale
Reaction timeC Limited, no effect foundC: small single-dose and 4-week trials in healthy adults with inconsistent results (evidence is mixed)Industry-fundedShort-term onlyWhy C grade for Reaction time: explainedApproved of the Reaction time grade
Perceived stressC Limited, no effect foundC: small or pilot studies with within-group or uncontrolled signals; the largest controlled trial did not report lion's mane alone beating placeboIndustry-fundedSubjective outcome onlyShort-term onlyWhy C grade for Perceived stress: explainedApproved of the Perceived stress grade
Global cognitionC LimitedC: small RCTs whose positive results come from older adults and clinical populations, extrapolated to healthy adultsIndustry-fundedWhy C grade for Global cognition: explainedApproved of the Global cognition grade

Grades describe evidence for each outcome, not a recommendation. Open a grade for its rationale and dated grade history. How we grade

The human evidence is a set of small trials using different products, doses and populations. A 2025 systematic review found five randomized controlled trials and three pilot clinical trials [4], but could not perform a meta-analysis (a statistical pooling of trials) because reporting was incomplete and unclear [4]. As of November 11, 2026 we found no meta-analysis pooling lion's mane trials (PubMed search, November 11, 2026). Grades are built from individual trials. See our memory, focus and mood and stress hubs for how lion's mane compares with other options.

Does lion's mane improve memory and cognitive function?

The positive results come from older adults, most of them in clinical populations. In a randomized, double-blind trial in 30 Japanese adults aged 50 to 80 with diagnosed mild cognitive impairment, the lion's mane group scored higher than placebo on a cognitive function scale at weeks 8, 12 and 16; the first author worked at the Mushroom Laboratory of Hokuto Corporation, a mushroom producer [1]. Scores fell significantly 4 weeks after participants stopped [1]. Results in this clinical population may not apply to healthy adults.

In a 12-week randomized, double-blind trial in 31 healthy Japanese adults with an average age of about 61, the lion's mane group improved on the Mini Mental State Examination (MMSE) [2][4]. The same trial also used a visual memory test and a verbal paired-associate learning test, and only the MMSE showed an effect [2].

A 49-week pilot trial in Taiwan randomized 49 people with mild Alzheimer's disease, a clinical population, to erinacine A-enriched mycelium capsules or placebo; Grape King Bio, the maker of the capsules, paid five of the authors' salaries and supplied research materials [3]. MMSE scores improved in the mycelium group while another screening score fell in the placebo group; 41 participants completed the study [3]. Results may not apply to healthy adults.

The 2025 systematic review reported a combined weighted mean MMSE increase of 1.17 points from one randomized trial and one pilot trial [4]. A separate evidence review described the trial in mild cognitive impairment as very small and its improvement as temporary and not yet replicated [13].

In healthy younger adults, an 18-person single-dose crossover trial found no significant effect on composite global cognition; two authors were employed by Beyond Alcohol Ltd. (Three Spirit Drinks), which also contributed towards the publication fee [6].

Does lion's mane improve reaction time and mental speed?

Evidence is mixed. Trials in healthy younger adults are small, mostly single-dose, and report effects on isolated tasks.

  • In a randomized, double-blind pilot trial of 1.8 g a day in healthy adults aged 18 to 45 (43 in the single-dose analysis, 41 at 28 days), the lion's mane group was quicker on the Stroop task (an attention test) 60 minutes after a single dose; the manufacturer, Sempera Organics, supplied the capsules, with no other external funding [5]. The authors noted null and some negative findings and urged caution given the small sample [5].
  • In a crossover trial of single doses in 40 healthy adults, part-funded by the extract supplier Applied Food Sciences, 1 g of lion's mane improved reaction time on the N-Back (a working-memory task) and the Go/No-go task (a test of holding back a response), and increased the number of attempts on Serial 7s (counting backward by sevens), measured 1 and 2 hours after the dose [7].
  • In a crossover trial in 18 healthy adults aged 18 to 35, 3 g of a 10:1 fruiting body extract had no significant effect on composite measures of overall cognition or mood compared with placebo; two authors were employed by Beyond Alcohol Ltd. (Three Spirit Drinks), which uses lion's mane in its products and contributed towards the publication fee [6]. Its only individual improvement was on a pegboard test at 90 minutes [6].
  • In a single-blind trial in 24 college-age adults, 10 g a day for 4 weeks, eaten in muffins, had no impact on cognition compared with placebo muffins [8].
  • In an uncontrolled pilot in 10 healthy adults taking 2 g a day for 28 days, executive function (planning and mental control) did not change significantly; M2 Ingredients supplied the product, a grant from the International Society of Sports Nutrition (itself sponsored by supplement companies) funded it, and three authors worked for Substantiation Sciences [9].

Significant results appeared on different tasks in different trials, and all three single-dose trials had commercial ties (donated product [5], company-employed authors and a publication-fee contribution [6], supplier funding [7]), so a consistent effect on reaction time has not been shown.

Does lion's mane reduce stress or improve mood?

Controlled trials in healthy young adults do not show a clear effect of lion's mane alone. In the 28-day trial of 1.8 g a day, there was only a non-significant trend towards lower subjective stress (p = 0.051); the manufacturer, Sempera Organics, supplied the capsules [5].

The largest trial randomized 84 women aged 18 to 26 who reported stress or anxiety to 1.8 g a day of lion's mane, 1.8 g a day of a lion's mane and reishi blend, or placebo for 28 days [10]. The blend lowered scores on the primary anxiety questionnaire (GAD-7) relative to lion's mane alone, and all groups, including placebo, improved on every psychological measure [10]. This trial was funded internally by Northumbria University, with products supplied by the manufacturer, Sempera Organics [10].

Other signals come from weaker designs. In a 4-week trial in 30 women studied for menopausal symptoms, mood and sleep, mood (CES-D) and complaints-index scores fell within the lion's mane cookie group, but differences from placebo were reported only on two complaints-index items [11]. An 8-week study of 77 adults with overweight or obesity and mood or sleep problems, a clinical population, reported better mood and sleep questionnaire scores while participants also followed a low-calorie diet; with no placebo group, the design cannot separate the supplement from the diet or other changes, and the manufacturer, A.V.D. Reform, provided the supplement [12]. These results may not apply to healthy adults.

What the evidence does not show

  • Benefits in healthy younger adults beyond isolated tests: overall cognition did not change in an 18-person single-dose trial with company-linked authors or a 24-person 4-week trial [6][8].
  • Lasting effects after stopping: in the company-linked trial in mild cognitive impairment, scores fell within 4 weeks of the last dose [1].
  • Sleep: sleep questionnaires were secondary measures in small studies, one without a placebo group and with manufacturer-provided supplement [11][12], so we have not graded sleep.

Doses used in studies

Ranges researchers used, not dosing advice. Bars share one scale. Read our disclaimer.

Older adults with mild cognitive impairmentfour 250 mg tablets three times a day (3.0 g/day) for 16 weeks250 mg
Healthy older adults3.2 g/day fruiting body powder for 12 weeks

3.2 g/day fruiting body powder for 12 weeks

Mild Alzheimer's disease (clinical population)three 350 mg erinacine A-enriched mycelium capsules a day for 49 weeks350 mg
Younger adults (healthy, or young women reporting stress or anxiety)1 g to 3 g of extract as a single dose; 1.8 g/day to 10 g/day for 4 weeks

1 g to 3 g of extract as a single dose; 1.8 g/day to 10 g/day for 4 weeks

Timing and form

Trials measured single-dose effects at 60 minutes (manufacturer-donated capsules) [5], 90 minutes (company-employed authors) [6] and 1 and 2 hours (supplier part-funded) [7]. Longer trials ran from 4 weeks [8][10] (the latter with donated products) to 16 weeks, by a mushroom company researcher [1], and 49 weeks, run with the product maker's staff [3]. In the 16-week trial, cognitive scores fell within 4 weeks of stopping [1].

The authors of the company-linked single-dose trial say the time for lion's mane compounds to peak in the human brain is not yet established, and note that people often eat up to 300 g of fresh fruiting body as mushroom steaks [6]. Supplement forms studied include fruiting body powders [4][11] and extracts [6], mycelium (in an industry-run trial) [3] and mycelium-fruiting body blends (manufacturer-supplied) [9]. In the EU, mycelium powder was classed as a novel food, while two specified fruiting-body extract powders were recorded as not novel (see below) [21].

What it is

Lion's mane (Hericium erinaceus) is an edible mushroom that grows on dead hardwood trees and has long, white, hanging spines that resemble a lion's mane [24]. Other names include yamabushitake, hou tou gu and monkey head mushroom [24]. It has a long history of use in Native American and East Asian medical systems [24]. It is eaten raw, dried or cooked, and sold as capsules, powders and liquid extracts [24].

Hericenones are extracted from the fruiting body (the visible mushroom) and erinacines from the cultured mycelium (the root-like network), according to researchers from Grape King Biotechnology, a mycelium producer [15]. The mushroom also contains phenolic acids, polysaccharides, sterols and lactones [24].

How it is thought to work (mechanism)

In preclinical studies both hericenones and erinacines crossed the blood-brain barrier [24]. Compounds from the fruiting body stimulated nerve growth factor synthesis [11], and a review describes lion's mane compounds as able to stimulate its release [17]. A systematic review of cell and rodent studies reported that erinacines enhanced neurogenesis (the formation of new nerve cells) and cell survival in animals [18]. These are mechanism findings and do not show an effect in people.

The claim that lion's mane regrows brain cells rests on this work, which also reports neurite growth (nerve cell branching), mostly with erinacine-rich mycelium extracts [13][17][18]. As of November 11, 2026 we found no human trial that measured nerve cell growth after lion's mane (PubMed and Europe PMC searches, November 11, 2026). We do not grade neurogenesis, because it is a mechanism rather than an outcome measured in people.

The closest human data are blood levels of BDNF, a growth factor. An uncontrolled 10-person pilot found no significant change in plasma BDNF after 28 days; the product was manufacturer-supplied and three authors worked for Substantiation Sciences [9]. An uncontrolled study in adults with overweight or obesity found higher pro-BDNF (the precursor of BDNF) but no significant change in BDNF; the manufacturer, A.V.D. Reform, provided the supplement [12]. Blood BDNF is not a measure of new neurons. See Does lion's mane regrow brain cells?.

Safety and interactions

What sources report. In a 49-week trial in people with mild Alzheimer's disease, run with Grape King Bio staff, four participants dropped out because of abdominal discomfort, nausea or skin rash [3]. A case report described acute respiratory failure in a 63-year-old man who had taken a lion's mane extract product, with lymphocyte reactivity to the extract [14]. One anaphylactic case was reported after a patient ate fresh lion's mane mushroom [13].

Who sources say should be careful.

  • People who are pregnant or breastfeeding: a Health Canada-licensed product label says to consult a health care practitioner before use [22].
  • People taking supplements rather than food: MSKCC advises talking with healthcare providers before taking lion's mane supplements [24].
  • People who have reacted to lion's mane before: the case reports above describe acute respiratory failure and anaphylaxis [13][14].

Trials have reported few side effects, but most were small. In the 16-week trial by a mushroom company researcher, laboratory tests showed no adverse effect [1]; a systematic review reports mild stomach discomfort and diarrhea in 7 people on lion's mane and 6 on placebo in that trial [4]. In the 49-week industry-run trial, 3 people on mycelium and 1 on placebo dropped out because of side effects, including abdominal discomfort, nausea and skin rash [3]. In the 84-person trial, which used manufacturer-donated products, 50 adverse events were reported by 31 participants, with no significant difference in frequency between groups [10]. The supplier-funded crossover reported no adverse events with lion's mane [7].

Memorial Sloan Kettering Cancer Center (MSKCC) lists abdominal discomfort, nausea and skin rash as possible side effects [24]. The 2025 systematic review lists stomach discomfort, headache and allergic reactions as potential side effects that are commonly unreported [4].

Two case reports describe severe reactions. A 63-year-old man needed intensive care for acute respiratory failure after taking a lion's mane extract product, with strong lymphocyte reactivity to the extract; he recovered with steroid treatment [14]. An evidence review notes one anaphylactic case after a person ate fresh lion's mane [13]. Single case reports cannot show how often such reactions happen.

In rats, studies by Grape King researchers, makers of the tested mycelium, found no toxic effects over 13 weeks at up to 2625 mg/kg body weight [16] and a no-observed-adverse-effect level above 3 g/kg body weight a day over 28 days [15]. These are animal studies.

As of November 11, 2026, the sources we checked (an NCCIH site search and an NCBI Bookshelf search covering LiverTox) have no lion's mane page, and we found no regulator upper intake level in any market.

Interactions sources report

MSKCC notes that herbal supplements are stronger than culinary herbs and can interact with medications [24]. As of November 11, 2026 we found no clinical drug-interaction studies of lion's mane (PubMed search, November 11, 2026). The MSKCC text we retrieved gives only this general caution; its interaction section did not load, so specific interactions remain unverified. If you take any medicines, talk to your doctor or pharmacist before combining them with lion's mane.

FAQ

Does lion's mane regrow brain cells?

Cell and rodent studies report that lion's mane compounds stimulate nerve growth factor and neurogenesis [17][18]. As of November 11, 2026 we found no human trial that measured nerve cell growth (PubMed and Europe PMC searches, 2026-11-11). Human studies have measured blood BDNF instead, with no significant change in a 10-person uncontrolled pilot using manufacturer-supplied product, with three authors from Substantiation Sciences [9].

How long did studies run?

Single-dose trials measured effects from 60 minutes to 2 hours after the dose; one used manufacturer-donated product, one had authors from a company selling lion's mane and one was part-funded by the extract supplier [5][6][7]. Longer trials ran up to 16 weeks in adults with mild cognitive impairment, in a trial by a mushroom company researcher [1], and 49 weeks in people with mild Alzheimer's disease, a clinical population, in a trial run with the product maker's staff [3]. In the 16-week company-linked trial, scores fell again within 4 weeks of stopping [1].

Is lion's mane safe?

Memorial Sloan Kettering Cancer Center (MSKCC) describes it as generally safe in food and tea and advises talking with a healthcare provider before taking supplements [24]. An industry-run trial reported abdominal discomfort, nausea and skin rash [3], and two case reports describe acute respiratory failure and anaphylaxis [13][14]. Talk to a clinician about your own situation.

What is the difference between fruiting body and mycelium products?

Hericenones are extracted from the fruiting body and erinacines from the cultured mycelium, according to researchers from a mycelium producer [15]. In the EU, dehydrated mycelium powder was classed as a novel food in 2019, while two specified fruiting-body extract powders were recorded as not novel in 2025 and 2026 [21].

References

  1. Mori K, Inatomi S, Ouchi K, et al. Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial. Phytother Res. 2009.PMID 18844328DOI 10.1002/ptr.2634Tier 1, RCT
  2. Saitsu Y, Nishide A, Kikushima K, et al. Improvement of cognitive functions by oral intake of Hericium erinaceus. Biomed Res. 2019.PMID 31413233DOI 10.2220/biomedres.40.125Tier 1, RCT
  3. Li IC, Chang HH, Lin CH, et al. Prevention of Early Alzheimer's Disease by Erinacine A-Enriched Hericium erinaceus Mycelia Pilot Double-Blind Placebo-Controlled Study. Front Aging Neurosci. 2020.PMID 32581767DOI 10.3389/fnagi.2020.00155Tier 1
  4. Menon A, Jalal A, Arshad Z, et al. Benefits, side effects, and uses of Hericium erinaceus as a supplement: a systematic review. Front Nutr. 2025.PMID 40959699DOI 10.3389/fnut.2025.1641246Tier 1, systematic review
  5. Docherty S, Doughty FL, Smith EF. 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. 2023.PMID 38004235DOI 10.3390/nu15224842Tier 1, RCT
  6. Surendran G, Saye J, Binti Mohd Jalil S, et al. Acute effects of a standardised extract of Hericium erinaceus (Lion's Mane mushroom) on cognition and mood in healthy younger adults: a double-blind randomised placebo-controlled study. Front Nutr. 2025.PMID 40276537DOI 10.3389/fnut.2025.1405796Tier 1
  7. La Monica MB, Raub B, Ziegenfuss EJ, et al. Acute Effects of Naturally Occurring Guayusa Tea and Nordic Lion's Mane Extracts on Cognitive Performance. Nutrients. 2023.PMID 38140277DOI 10.3390/nu15245018Tier 1, RCT
  8. Grozier CD, Alves VA, Killen LG, et al. Four Weeks of Hericium erinaceus Supplementation Does Not Impact Markers of Metabolic Flexibility or Cognition. Int J Exerc Sci. 2022.PMID 36582308DOI 10.70252/XZKO8571Tier 1
  9. Evans C, Kalman D, Goodrich J, et al. A Pilot Proof-of-Concept Study to Evaluate the Physiological and Cognitive Impacts of Hericium erinaceus on Healthy Adults. Nutrients. 2026.PMID 42884628DOI 10.3390/nu18193177Tier 1
  10. Smith EF, Docherty S. The effects of four-week supplementation of Lion's mane and a Lion's mane and Reishi blend on prioritised mood and wellbeing measures in young women. Front Nutr. 2026.PMID 42978868DOI 10.3389/fnut.2026.1887408Tier 1, controlled trial
  11. Nagano M, Shimizu K, Kondo R, et al. Reduction of depression and anxiety by 4 weeks Hericium erinaceus intake. Biomed Res. 2010.PMID 20834180DOI 10.2220/biomedres.31.231Tier 1, RCT
  12. Vigna L, Morelli F, Agnelli GM, et al. Hericium erinaceus Improves Mood and Sleep Disorders in Patients Affected by Overweight or Obesity: Could Circulating Pro-BDNF and BDNF Be Potential Biomarkers?. Evid Based Complement Alternat Med. 2019.PMID 31118969DOI 10.1155/2019/7861297Tier 1
  13. Muhanna M, Lund I, Bromberg M, et al. ALSUntangled #73: Lion's Mane. Amyotroph Lateral Scler Frontotemporal Degener. 2024.PMID 38141002DOI 10.1080/21678421.2023.2296557Tier 1
  14. Nakatsugawa M, Takahashi H, Takezawa C, et al. Hericium erinaceum (yamabushitake) extract-induced acute respiratory distress syndrome monitored by serum surfactant proteins. Intern Med. 2003.PMID 14714963DOI 10.2169/internalmedicine.42.1219Tier 1
  15. Li IC, Chen YL, Lee LY, et al. Evaluation of the toxicological safety of erinacine A-enriched Hericium erinaceus in a 28-day oral feeding study in Sprague-Dawley rats. Food Chem Toxicol. 2014.PMID 24810469DOI 10.1016/j.fct.2014.04.040Tier 1
  16. Lee LY, Li IC, Chen WP, et al. Thirteen-Week Oral Toxicity Evaluation of Erinacine AEnriched Lion's Mane Medicinal Mushroom, Hericium erinaceus (Agaricomycetes), Mycelia in Sprague-Dawley Rats. Int J Med Mushrooms. 2019.PMID 31002635DOI 10.1615/IntJMedMushrooms.2019030320Tier 1
  17. Szućko-Kociuba I, Trzeciak-Ryczek A, Kupnicka P, et al. Neurotrophic and Neuroprotective Effects of Hericium erinaceus. Int J Mol Sci. 2023.PMID 37958943DOI 10.3390/ijms242115960Tier 1, narrative review
  18. Spangenberg ET, Moneypenny A, Bozzo GG, et al. Unveiling the role of erinacines in the neuroprotective effects of Hericium erinaceus: a systematic review in preclinical models. Front Pharmacol. 2025.PMID 40626304DOI 10.3389/fphar.2025.1582081Tier 1, narrative review
  19. U.S. Food and Drug Administration. Questions and Answers on Dietary Supplements. not shown in fetched text.SourceTier 1
  20. Food Standards Agency. Novel foods authorisation guidance. Published May 30, 2018 (page as fetched).SourceTier 1
  21. European Commission. Consultation process on novel food status. not shown in fetched text; entries dated up to September 22, 2026.SourceTier 1
  22. Health Canada. Licensed Natural Health Products Database: Lion's Mane (NPN 80070799). Revised date of licence 2020-08-14.SourceTier 1
  23. Health Canada. Natural Health Products Ingredients Database: beta-glucan. not shown in fetched text.SourceTier 1
  24. Memorial Sloan Kettering Cancer Center. Lion's Mane Mushroom (About Herbs). Updated November 19, 2025.SourceTier 2
  25. Australian Government, Department of Health, Disability and Ageing (Federal Register of Legislation). Therapeutic Goods (Permissible Ingredients) Determination (No. 3) 2026 (F2026L01382), volumes 1-6. Updated October 13, 2026.SourceTier 1
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