Evidence Trace, complete trial record

In plain terms

In plain terms: Lion's Mane Mushroom shows early signals in human research but the evidence is limited -- small trials, surrogate endpoints, or not yet independently replicated. It is an emerging area, not yet a proven one.

Lion's Mane Mushroom

C Limited: small, mixed or unreplicated trials

Category Supplements

Evidence Small randomized trials on measured cognitive tests

Reviewed July 2026

PMIDs 18844328 · 31413233 · 36582308 · 38004235 · 40276537 · 32581767 · 40959699

The endpoint this grade is based on: Objectively measured functional outcome, Cognitive test scores in older adults with mild cognitive impairment, on one small positive trial of fruiting-body powder and one partial replication. No cited trial measured nerve growth factor, nerve repair or mood; those are mechanisms from laboratory work or uncited small studies. Benefit has not been shown in healthy adults.

The evidence as the record states it

Evidence record

PMID 18844328 PMID 31413233 PMID 36582308 PMID 38004235 PMID 40276537 PMID 32581767 PMID 40959699

Mori et al. (Phytotherapy Research, 2009; PMID 18844328): randomized double-blind trial, 30 adults aged 50 to 80 with mild cognitive impairment, about 3 g/day of fruiting-body powder for 16 weeks; clinician-administered HDS-R cognitive scores higher than placebo at weeks 8 to 16 and lower again four weeks after stopping. The lead author's affiliation is the mushroom laboratory of a commercial mushroom producer; funding is not stated. Saitsu et al. (Biomedical Research, 2019; PMID 31413233): 31 healthy older adults, fruiting body for 12 weeks; the Mini-Mental State Examination improved while the Benton visual retention and verbal paired-associate tests did not, a partial result rather than a confirmation, at a dose the abstract does not state. Null or mostly null in healthy young adults: Grozier et al. (Int J Exerc Sci, 2022; PMID 36582308), 10 g/day for 4 weeks; Docherty et al. (Nutrients, 2023; PMID 38004235), 1.8 g/day for 28 days, faster Stroop after a single dose and otherwise null; Surendran et al. (Front Nutr, 2025; PMID 40276537), single 3 g dose of extract, null on composite cognition and mood. Different form: Li et al. (Front Aging Neurosci, 2020; PMID 32581767), erinacine-enriched mycelium 1,050 mg/day for 49 weeks in mild Alzheimer's disease, MMSE and daily-living scores better than placebo, maker-run; four participants withdrew for abdominal discomfort, nausea or rash. Menon et al. (Front Nutr, 2025; PMID 40959699): systematic review of five randomized trials; pooled MMSE gain about 1.2 points from one trial and one pilot; side effects listed include stomach discomfort, headache and allergic reactions. Grade C: one small positive trial on measured cognitive tests in impaired older adults, a partial second, nulls in healthy adults.

PMID 18844328 PMID 31413233 PMID 36582308 PMID 38004235 PMID 40276537 PMID 32581767 PMID 40959699

Why Grade C and not Grade B

Grade C reflects early or limited human evidence -- small trials, surrogate endpoints, or preliminary findings not yet independently replicated. The evidence points in a promising direction but does not yet meet the standard for Grade B. A single well-powered, independently replicated trial with a meaningful endpoint would move this to Grade B or higher.

What this grade covers and what it does not

Grade C on measured cognitive tests in older adults with mild cognitive impairment. One small double-blind trial (Mori et al., 2009; PMID 18844328; 30 adults, about 3 g/day of fruiting-body powder for 16 weeks) found clinician-administered HDS-R scores higher than placebo, falling after stopping; its lead author worked at a commercial mushroom producer's laboratory, stated beside the letter. Saitsu et al. (2019; PMID 31413233) improved one of three cognitive tests in healthy older adults, a partial result. Trials in healthy young adults were null or mostly null (PMIDs 36582308, 38004235, 40276537). A single clean positive trial with a partial second is C. WHAT THIS GRADE DOES NOT COVER: nerve growth factor, neuroplasticity, nerve repair and mood, which no cited trial measured; healthy adults, in whom benefit has not been shown; the 500 to 1,000 mg extract doses sold, which no positive chronic trial used; and erinacine-enriched mycelium (Li et al., 2020; PMID 32581767), a different form tested in mild Alzheimer's disease by its maker. Aligned with the lion's mane protocol at C.

What would move this grade

A well-powered randomized trial with an objective, clinically meaningful primary endpoint and at least one independent replication would support Grade B or higher.

How to track whether this is working A measured cognitive test (MoCA or MMSE) at baseline and 12 to 16 weeks, which is what the trials used; no mood or nerve outcome was measured in any cited trial.