Lion’s mane: does it improve memory or focus?

What is lion’s mane?

Lion’s mane (Hericium erinaceus) is used as a food and sold in powders, capsules and extracts. Products may use different parts of the fungus and manufacturing methods, so a result for one preparation does not automatically apply to another. Laboratory and animal studies can suggest questions about nerve signalling but do not establish a human clinical benefit.4

What did studies in healthy adults find?

In a 2023 placebo-controlled pilot study, 41 healthy adults aged 18–45 received a particular preparation or placebo for 28 days. Researchers reported faster performance on one attention-related task after the first administration, but many other findings were null or limited; a suggested reduction in self-reported stress did not meet the conventional threshold for statistical significance. The supplier, Sempera Organics, provided the product; the authors said it had no role in design, analysis or publication.

In a separate 2025 crossover study, 18 healthy adults completed tests after one administration of a different extract and after placebo. There was no significant overall difference in combined cognitive or mood measures, although one individual task favoured the extract and other test results went in the opposite direction. Two authors worked for Beyond Alcohol, which sells products containing lion’s mane; the company contributed to the publication fee. Small studies with many measures can produce isolated findings; neither establishes lasting everyday benefits.12

What about older people or dementia?

A 2009 placebo-controlled trial randomized 30 Japanese adults aged 50–80 with mild cognitive impairment to a mushroom preparation or placebo; 29 were included in the analysis. The mushroom group scored higher on a modified cognitive scale during the 16-week treatment period; scores declined after supplementation stopped. A short score change in this selected group does not show prevention of dementia, improved independence or benefit from every product. Four of the five authors were affiliated with Hokuto, which grew the mushrooms used in the trial; the report did not identify a funding source. Memory problems can have many causes and deserve clinical evaluation.

A separate 2020 pilot trial studied people already diagnosed with mild Alzheimer’s disease; despite the paper’s title, it was not a prevention trial. Forty-nine participants were randomized to a specific mushroom mycelium preparation or placebo, and 41 completed the study. At week 49, the authors reported a difference between groups on a questionnaire about everyday activities. Scores on two cognitive screening tests did not differ significantly between groups; an improvement within one group alone does not establish an effect versus placebo. The small analysis, withdrawals and multiple measures limit interpretation, and it does not show that lion’s mane prevents dementia. The company Grape King Bio supplied materials and paid several authors, although the authors reported no additional role in study design or analysis.35

Safety and product questions

Memorial Sloan Kettering lists abdominal discomfort, nausea and rash among possible effects. In the 2009 trial, stomach discomfort or diarrhoea was reported in seven of the 14 analysed participants in the mushroom group and six of the 15 in the placebo group; another mushroom-group participant withdrew after reporting stomach discomfort. These reports do not establish what caused the symptoms. Short studies cannot establish long-term safety, rare allergic reactions or all interactions. The amount and composition of mushroom powders and extracts can vary; a label or a laboratory mechanism is not proof of quality or effectiveness. Ask a pharmacist or clinician about a specific product, particularly if you take medicines or have a health condition. Seek emergency help for severe allergic symptoms. For another cognition claim, see creatine and brain function; compare labels with the supplement label guide.43