Lion's mane (Hericium erinaceus): what studies show about memory, mood and side effects

**Research review** ## The hook Lion's mane is often called a "brain mushroom". Channel posts promised new neurons, memory, sleep and help with disease. Let us check what the research supports, and what it does not. ## In brief - Lion's mane contains compounds that stimulate nerve growth factor (NGF) in cells and mice [S-004, S-010, S-005]. That does not show the same effect in humans. - Human studies are few and small. One placebo-controlled trial in older adults with mild cognitive impairment reported better scores, but a single trial is not proof [S-001]. - A 2025 systematic review found five randomised trials but warns that side effects are "commonly unreported" [S-008]. - A 2026 pilot in 10 adults found no significant change in executive function or plasma BDNF [S-009]. ## What the human studies show - **Mild cognitive impairment, 2009.** 30 Japanese adults aged 50–80 took lion's mane tablets or placebo for 16 weeks. Cognitive scale scores in the lion's mane group were significantly higher than placebo at weeks 8, 12 and 16, and fell within four weeks after stopping [S-001]. These are protocol data, not a recommendation: participants took four 250 mg tablets three times a day. - **Mood and menopause, 2010.** 30 women took lion's mane cookies or placebo for 4 weeks. Depression scores and some complaints fell, and on two items the lion's mane group was better than placebo [S-002]. The sample was small, there was no depression diagnosis, and the abstract gives no sleep results. - **Pilot, 2026.** 10 adults aged 18–55 took 2 g a day for 28 days. There were no significant changes in executive function or plasma BDNF; effects were small and unproven [S-009]. - **Review, 2025.** The authors report a combined weighted mean increase of 1.17 on the Mini-Mental State Examination in the intervention groups of one trial and one pilot. This is a pooled figure from two small studies [S-008]. ## What cell and animal studies show - **Cells, NGF.** A lion's mane extract increased NGF output in astrocytoma cells; the individual hericenones C, D and E did not reproduce this [S-004]. Isoindolinone compounds from the fruiting body increased NGF and neurite outgrowth in cell lines [S-010]. - **Mice, memory.** In mice given amyloid β(25–35), lion's mane prevented memory deficits in behavioural tests [S-003]. This is not the same as "preventing plaque formation": plaques were not measured in this study. - **Mice, mood and hippocampus.** Lion's mane extracts reduced anxiety- and depression-like behaviour and increased cell proliferation in the hippocampus [S-007, S-006]. Doses in these studies (20–400 mg/kg) are animal data, not a human dose. - **Mice, memory and neurotrophins.** Compounds from lion's mane activated the BDNF pathway and improved spatial memory [S-005]. ## What we do not carry over from the posts - Claims about Alzheimer's, cancer, diabetes, cardiovascular disease, ulcers, stroke, brain injury, insomnia and cortisol. These are claims about treating or preventing disease. The studies we found do not include human trials that confirm them; most evidence is cell or animal work, or none. - "No addiction effect was recorded": no source. - Side effects from the posts (drowsiness, irritability, migraines). The systematic review lists stomach discomfort, headache and allergic reactions, but not drowsiness or irritability. We do not claim them. - Advice on alcohol, diet, and sales of lion's mane chocolate. These are not scientific findings. ## What is known, what is not, and the risks **Known:** lion's mane is studied in cells, animals and a small number of people. In humans there are two small trials with positive scale results and one pilot with no significant change [S-001, S-002, S-009]. **Not known:** whether lion's mane affects memory or mood in people in everyday life; which form (fruiting body, mycelium, extract) and which dose would matter; how it interacts with medicines. **Risks:** the 2025 review says side effects are rarely reported. It mentions stomach discomfort, headache and allergic reactions [S-008]. If you are pregnant, breastfeeding, take medicines or have a chronic condition, discuss use with a doctor first. This article gives no guidance on use. ## Vegetarian alternatives The mushroom itself suits vegetarians and vegans. But finished products can contain gelatin (in capsules) or dairy (in chocolate and biscuits). If you are vegetarian or vegan, choose plant-based capsules and read the label. ## Question for readers What seems most convincing about "brain mushrooms" to you, and what makes you doubt it? ## What was verified and what was meant | Claim | Status | Source | |---|---|---| | Lion's mane increases NGF output in cells | verified against the abstract; cells, not humans | S-004, S-010 | | Hericenones C, D and E did not increase NGF in cells | verified against the abstract | S-004 | | Placebo-controlled trial, 30 people, 16 weeks, better HDS-R scores | verified against the abstract; small sample | S-001 | | Scores fell within 4 weeks after stopping | verified against the abstract | S-001 | | Lion's mane cookies: lower depression scores and some complaints in 30 women over 4 weeks | verified against the abstract; small sample | S-002 | | Sleep and menopause as outcomes: no results in the abstract | not confirmed | S-002 | | Pilot in 10 people: no significant change in memory or BDNF | verified against the abstract | S-009 | | 2025 review: 5 RCTs; side effects "commonly unreported" | verified against the abstract | S-008 | | 2025 review: 1.17-point MMSE increase in lion's mane groups | verified against the abstract; pooled figure from two trials | S-008 | | Lion's mane prevented memory deficits in mice given amyloid | verified against the abstract; animals | S-003 | | Lion's mane "prevents plaque formation" (post #31) | not confirmed: plaques were not measured in the study | S-003 | | Extract reduced anxiety-like behaviour and increased hippocampal proliferation in mice | verified against the abstract; animals | S-007, S-006 | | Hericenone-type compounds improved memory in mice (post #135) | verified against the abstract; animals | S-005 | | Lion's mane treats cancer, diabetes, ulcers, cardiovascular disease, Alzheimer's, stroke (posts #31, #53, #150) | not confirmed; treatment claims not carried over | — | | Side effects: drowsiness, irritability, migraine (post #169) | not in the review; not claimed | S-008 | | No addiction effect (post #31) | no source | — | | Author's personal experience | not provided; no block added | — | Author: Serge Luboff. Reviewer: not assigned. Medical review: not performed. This material is not medical advice and does not replace consultation with a doctor.