The short answer
Possibly, in older adults with mild memory decline. Three small placebo-controlled trials, in Japan and Taiwan, found better scores on short memory tests after 12 to 49 weeks of 1 to 3.2 g a day. The gains were modest, faded after stopping in one trial, and no large trial has confirmed them.
Moderate evidence
More than one small placebo-controlled trial points the same way, but none is large enough to settle it. How we grade
On this page
What did the memory trials find?
Three placebo-controlled trials have tested lion’s mane on memory in older people, and all three reported some benefit:
| Trial | Who | Dose and length | Result |
|---|---|---|---|
| Mori 2009, Japan | 30 adults aged 50 to 80 with mild cognitive impairment | 3 g a day of fruiting body powder for 16 weeks | Scores on a dementia rating scale rose steadily compared with placebo from week 8, then fell back within 4 weeks of stopping |
| Saitsu 2019, Japan | 31 adults over 50, average age 61 | 3.2 g a day of fruiting body powder for 12 weeks | Better scores on the Mini-Mental State Examination (MMSE); no difference on two other memory tests |
| Li 2020, Taiwan | 41 people with mild Alzheimer’s disease | 1.05 g a day of mycelium rich in erinacine A for 49 weeks | MMSE scores improved with lion’s mane; the placebo group declined on another thinking test; daily living scores differed between groups |
A 2025 systematic review combined the MMSE results of two lion’s mane trials and found an average gain of about 1.2 points on the 30-point scale. That is a small change on a test designed to screen for dementia rather than to measure fine differences.
How much should we trust these results?
We grade this claim as moderate evidence: the trials agree in direction, but each is small and none settles the question. The main limits are:
- Size. Between them the three trials put fewer than 60 people on lion’s mane.
- Short tests. The MMSE and similar scales are screening tools. They are not sensitive to small changes, and a one-point shift can happen by chance.
- Mixed outcomes within trials. In Saitsu 2019 only one of three memory tests improved.
- Funding. In Li 2020 the company that makes the mycelium product paid the salaries of several authors. That does not make the result wrong, but it is a reason to want an independent repeat.
- No large trial. No trial with hundreds of participants, or one run outside East Asia in older adults, has been published.
Why might lion’s mane affect memory?
In cell and animal studies, hericenones and erinacines raise nerve growth factor, protect nerve cells from damage and reduce inflammation. A 2025 systematic review of the rodent and cell studies found that erinacine-rich mycelium extracts improved memory and movement in animals, in a dose-dependent way, and helped new nerve cells form and survive. Whether the same happens in people, at the doses in a capsule, is not known. The same lab findings lie behind claims that lion’s mane repairs nerves, which has not been tested in people either.
Should you try it for memory?
If you are an older adult with mild memory complaints and your GP has ruled out treatable causes, the trials suggest that 1 to 3 g a day of a fruiting body product, or a standardised erinacine-rich mycelium extract, taken for at least three months, is a reasonable thing to try. Expect a small effect at best, and note that in the one trial that checked, the benefit faded within a month of stopping.
Lion’s mane is not a treatment for dementia. If you or a relative has been diagnosed, keep to the treatment your doctors recommend and tell them about any supplement. See dosage and side effects before starting.
Keep reading
- Lion's mane for focus: does it work in healthy adults?
Five small trials tested lion's mane for focus and thinking in healthy adults. Most found no real effect. What was tested, and what the results mean.
Weak - Lion's mane for anxiety and depression: the evidence
Two small studies suggest lion's mane may ease anxiety and low mood, but neither is strong. What they found, their limits and who should be careful.
Weak - Lion's mane for nerve damage and neuropathy: what the evidence shows
Lion's mane helped injured nerves recover in rats and mice, but it has never been tested for nerve damage or neuropathy in people. What the studies found.
None
Common questions
Can lion's mane prevent dementia?
There is no evidence that it prevents dementia. One 49-week trial in 41 people with mild Alzheimer's disease found that memory test scores held up better than with placebo, but that is a small study funded by the product's maker and it has not been repeated.
How much lion's mane did the memory trials use?
Between 1.05 g a day of an erinacine-rich mycelium extract and 3.2 g a day of dried fruiting body powder, split into two to four doses with meals.
Does lion's mane help memory in young people?
The trials in healthy young adults found no lasting effect on memory. See our page on focus in healthy adults for the details.
References
- Mori K et al. Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial. Phytotherapy Research, 2009.pubmed.ncbi.nlm.nih.gov
- Saitsu Y et al. Improvement of cognitive functions by oral intake of Hericium erinaceus. Biomedical Research, 2019.pubmed.ncbi.nlm.nih.gov
- Li IC et al. Prevention of early Alzheimer's disease by erinacine A-enriched Hericium erinaceus mycelia: pilot double-blind placebo-controlled study. Frontiers in Aging Neuroscience, 2020.pubmed.ncbi.nlm.nih.gov
- Menon A et al. Benefits, side effects, and uses of Hericium erinaceus as a supplement: a systematic review. Frontiers in Nutrition, 2025.pubmed.ncbi.nlm.nih.gov
- Cha S et al. A review of the effects of mushrooms on mood and neurocognitive health across the lifespan. Neuroscience & Biobehavioral Reviews, 2024.pubmed.ncbi.nlm.nih.gov
- Spangenberg ET et al. Unveiling the role of erinacines in the neuroprotective effects of Hericium erinaceus: a systematic review in preclinical models. Frontiers in Pharmacology, 2025.pubmed.ncbi.nlm.nih.gov
First published 3 November 2026. Spotted an error? Tell us and we'll correct it. Read our editorial policy.