Food component

Lion's mane mushroom review — memory studies, evidence and side effects

Also known as: lions mane, lion's mane mushroom, Hericium erinaceus, yamabushitake

At a glanceLion's mane (Hericium erinaceus) is an edible mushroom sold as a brain supplement. Small trials give mixed results on memory and thinking; large trials are lacking.

What is lion’s mane?

Lion’s mane (Hericium erinaceus) is an edible mushroom that grows on dead hardwood trees. Its long white spines hang down like a lion’s mane, which gives it its name; in Japan it is called yamabushitake. It is eaten as food in East Asia and is also sold as dietary supplements in capsules, powders and liquid extracts.

Does lion’s mane help memory?

The evidence so far is thin. A handful of small trials have reported better scores on some cognitive tests, while others found little or no effect. No large trial has shown that lion’s mane improves memory or prevents cognitive decline, and in Korea it has no officially recognized function. The sections below set out what the laboratory work and the human trials actually found.

Compounds studied in the laboratory

In the early 1990s a research team led by Hirokazu Kawagishi isolated two groups of compounds from lion’s mane: hericenones from the mushroom itself (1991) and erinacines from its mycelium, the network of fine threads from which the mushroom grows (1994). In laboratory tests both stimulated the production of nerve growth factor (NGF), a protein that supports the growth and survival of nerve cells.

A 2025 systematic review of cell and rodent studies concluded that mycelium preparations and erinacines improved motor, cognitive and depression-like behaviors in animal models, in a dose-dependent way. Memorial Sloan Kettering’s summary also cites a mouse study in which lion’s mane extract improved memory linked to the hippocampus. These are animal and cell results; they do not show that the same happens in people.

Trials in people have used different preparations, including dried mushroom powder, mycelium enriched with erinacine A and mixed products, so a result for one preparation does not automatically apply to another.

What human trials found

Older adults. In a 2009 trial in Japan, 30 people aged 50 to 80 with mild cognitive impairment took either tablets of dried lion’s mane (twelve 250 mg tablets a day) or a placebo for 16 weeks. The lion’s mane group scored higher on a cognitive scale at weeks 8, 12 and 16, but its scores fell again four weeks after the tablets stopped (Mori et al., 2009).

A 2019 trial in Japan analyzed 31 healthy adults over 50 who took either supplements of powdered lion’s mane (3.2 g a day) or a placebo for 12 weeks. Scores on the Mini-Mental State Examination, a short screening test, improved in the lion’s mane group, but two other tests of visual memory and word-pair learning showed no difference between the groups (Saitsu et al., 2019).

A 49-week pilot trial in Taiwan gave people with mild Alzheimer’s disease capsules of lion’s mane mycelium enriched with erinacine A or a placebo, and reported better results than placebo on some cognitive and daily-living measures (Li et al., 2020). It was a small pilot study and does not show that lion’s mane treats or prevents the disease.

Healthy younger adults. Results are mixed. In a pilot trial of 41 adults aged 18 to 45, a single 1.8 g dose made people faster on a Stroop task an hour later. After 28 days of daily use, however, there was no treatment effect on overall cognitive scores, and the placebo group did better on delayed word recall (Docherty et al., 2023). In a crossover trial, a single 1 g dose improved reaction time on some tasks (La Monica et al., 2023). Another crossover trial in 18 young adults found no overall effect of a single extract dose on cognition or mood, apart from better performance on a pegboard task (Surendran et al., 2025). In a 2026 pilot study, ten healthy adults who took 2 g a day for four weeks showed no statistically significant change in executive function or in blood levels of BDNF, another growth factor (Evans et al., 2026).

Stress and mood. In the 2023 pilot trial, 28 days of lion’s mane produced only a trend toward lower self-rated stress that did not reach statistical significance. In a 2026 trial of 84 women aged 18 to 26 who reported stress or anxiety, a blend of lion’s mane and reishi mushroom lowered the main anxiety questionnaire score more than lion’s mane alone, and every group, including placebo, improved over the study (Smith and Docherty, 2026).

Each trial described here involved fewer than 100 participants, and a 2025 systematic review noted that the research is limited by small samples, short study periods and differences between studies.

Side effects and safety

The 2025 systematic review found that side effects were seldom reported, but listed stomach discomfort, headache and allergic reactions. In the 49-week Taiwanese trial, four participants dropped out because of abdominal discomfort, nausea or skin rash.

A 2003 report from Japan described a 63-year-old man who developed acute respiratory distress syndrome, a severe lung condition, after taking a lion’s mane extract. A lymphocyte stimulation test reacted strongly to the extract, and he recovered after intensive care (Nakatsugawa et al., 2003). The review describes this as a rare case.

Lion’s mane in Korea

Lion’s mane is not among the ingredients listed in Korea’s official notice on health functional foods (MFDS Notice No. 2026-43). The notice therefore gives it no recognized function, daily intake or official cautions.

Bottom line

Lion’s mane is an edible mushroom whose compounds stimulated nerve growth factor production in laboratory studies. Human trials are few and small, their results are mixed, and none shows that it prevents or treats cognitive decline or dementia. Concentrated supplements differ from the mushroom eaten as food, so people taking medication, or who are pregnant or breastfeeding, should talk with a health professional first.

This review does not recommend any product. If you take medication, are pregnant or breastfeeding, or have a health condition, talk to a doctor or pharmacist first.