Limited evidenceBrain & cognition

Lion's Mane Mushroom

The mechanism is genuinely interesting — erinacines and hericenones induce nerve growth factor in vitro — but the human evidence amounts to two small Japanese trials and a pilot in mild Alzheimer's. Promising, nowhere near proven.

What the science says

Mild cognitive impairment Limited evidence
In the most-cited trial, 30 Japanese adults aged 50-80 with MCI were randomized to 3 g/day (twelve 250 mg tablets of 96% dry powder) or placebo for 16 weeks. The treatment group scored significantly higher on an HDS-R-based cognitive scale at weeks 8, 12, and 16, but scores fell significantly within 4 weeks of stopping. With 15 people per arm and a single site, this is far too small to be conclusive.
Early Alzheimer's disease Limited evidence
A 49-week double-blind pilot gave three 350 mg capsules/day of erinacine A-enriched mycelia (5 mg/g erinacine A) to patients with mild AD. The treatment group showed better MMSE and IADL scores and better contrast sensitivity versus placebo, alongside favourable biomarker and DTI findings. It was a small pilot with many outcomes and no confirmatory trial has followed in the years since.
Mood, anxiety, and cognition in healthy adults Limited evidence
Several small acute-dosing and short-term studies in healthy people report changes in mood or reaction time, but findings are inconsistent across trials and no result has been independently replicated. There is no reliable evidence that lion's mane improves cognition in people without impairment.

Dosage & safety

Studied dose3 g/day of dried fruiting body powder (the MCI trial) or 1,050 mg/day of erinacine A-enriched mycelium (the Alzheimer's pilot), for 16-49 weeks. This matters: fruiting body supplies hericenones, mycelium supplies erinacines, and the two are chemically distinct and not interchangeable. Benefits in the MCI trial faded within a month of stopping.

SafetyWell tolerated in trials, though abdominal discomfort, nausea, and skin rash caused four dropouts in the 49-week Alzheimer's pilot. Contact dermatitis and one case report of acute respiratory distress following consumption have been described in sensitised individuals. Theoretical antiplatelet and glucose-lowering effects warrant caution with anticoagulants and antidiabetic drugs. Not studied in pregnancy or breastfeeding. Most consumer products declare neither beta-glucan, hericenone, nor erinacine content, and many mycelium-on-grain products are largely starch — meaning what is in the bottle often bears no relation to what was tested.

Scientific references

Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial
Mori K, Inatomi S, Ouchi K, Azumi Y, Tuchida T — Phytotherapy Research, 2009
Prevention of Early Alzheimer's Disease by Erinacine A-Enriched Hericium erinaceus Mycelia Pilot Double-Blind Placebo-Controlled Study
Li IC, Chang HH, Lin CH, Chen WP, Lu TH, Lee LY, Chen YW, Chen YP, Chen CC, Lin DP — Frontiers in Aging Neuroscience, 2020

Where to buy

Real Mushrooms, Lion's Mane, Mushroom Extract Powder, 120 Capsules

View on iHerb

Referral link — this site may earn a commission on purchases.

Related in Brain & cognition

Vitamin B2 (Riboflavin) Moderate evidence
Choline Moderate evidence
Magnesium L-Threonate Limited evidence
Phosphatidylserine Limited evidence
Lecithin (Phosphatidylcholine) Limited evidence
Agmatine Sulfate Limited evidence