Quick answer

Lion's mane is an edible mushroom. In two small trials, adults over 50 who took about 3 g a day of the powdered mushroom for 12 to 16 weeks scored slightly higher than with placebo on some memory and thinking tests. Studies in younger adults found little, so the evidence is graded early.^1,2,3

Key facts

Lion's mane has a long history as a food and in traditional Chinese medicine, mostly in East Asia.⁴
The fruiting body trials with positive results used about 3 to 3.2 g a day.^1,2
In the 16-week trial, scores fell back within 4 weeks of stopping.¹
NIH's LiverTox rates lion's mane an unlikely cause of liver injury.⁴

What lion's mane is

Lion's mane has been used widely as a food and as an herbal medicine in traditional Chinese medicine.⁴

The part you can see and cook is the fruiting body. It grows from the mycelium, a network of fine threads, and supplements may use either part or both. The two parts are not the same material, chemically:^5,6

Two groups of compounds set lion's mane apart: hericenones, taken from the fruiting body, and erinacines, taken from the cultured mycelium.⁵

Most of what is known about these compounds comes from cells and animals. In rats, an erinacine swallowed as a mycelium extract was later found in the brain, which is one reason the mushroom draws so much interest.⁷

NIH's LiverTox notes that the brain effects seen in cell and animal studies have not been shown to any great extent in humans.⁴

What the studies found

One claim has enough human research behind it to show here, and it is graded early: a few small trials that have not been repeated at scale. The amount those trials used is printed with it.

May support memory and thinking test scores in adults over 50 at about 3 g a day of fruiting body powder; not shown in younger adults*^1,2,3,6,8

Early evidence

Two small Japanese trials. In 30 adults aged 50 to 80 whose memory and thinking had been assessed as mildly below normal for their age, about 3 g a day of fruiting body powder for 16 weeks raised scores on a cognitive scale more than placebo at weeks 8, 12 and 16, and the gain faded within 4 weeks of stopping. In 31 adults over 50, 3.2 g a day for 12 weeks gave a slightly higher result than placebo on one screening test and no difference on two others. In younger adults, 10 g a day for 4 weeks changed nothing measured, and single doses of 1 to 3 g gave mixed results.

Amount studied: About 3 to 3.2 g a day of fruiting body powder for 12 to 16 weeks

Younger, healthy adults have been tested too, with weaker results. Single doses of 1 to 3 g, taken an hour or two before testing, produced a mix of small gains and losses on individual tasks, and 10 g a day for four weeks changed nothing that was measured.^3,6,8,9

Mood has been studied less. In a four-week trial in 30 women, a few answers on a questionnaire of everyday complaints differed from placebo, and a 28-day trial in young adults found a trend toward lower stress ratings that fell just short of statistical significance.^8,10

All of these trials were small. None of the placebo-controlled trials we found randomized more than 49 people, so a single new trial could change the picture.^8,9,11

How much was studied

About 3 g a day of fruiting body powder: four 250 mg tablets three times a day for 16 weeks in one trial, and 3.2 g a day for 12 weeks in the other.^1,2,8

Trials in younger adults used single doses of 1 g of fruiting body or 3 g of a 10:1 fruiting body extract, 1.8 g a day for 28 days, and 10 g a day for 4 weeks.^3,6,8,9

Trials gave weighed amounts in tablets, capsules, cookies or muffins. To compare a product with a study, compare grams of the same part of the mushroom: fruiting body powder, mycelium and extract are not interchangeable. The dosage guide lists every amount by trial.^1,3,6,10

Fruiting body, mycelium or extract

The fruiting body is the part of the mushroom that is cooked and eaten. Hericenones come from it, and it is the form used in the trials of about 3 g a day.^1,5,8

The mycelium is the network of threads the mushroom grows from. For supplements it is grown in culture, for example in liquid tanks, and it is the source of erinacines.^5,6,11

Extracts concentrate the mushroom with water or alcohol. One trial used 3 g of a 10:1 fruiting body extract made with water and ethanol and dried onto maltodextrin.⁶

Starch is a polysaccharide too, so a total polysaccharide figure on a label is not the same as beta-glucan. Beta-glucan tests measure total glucan and subtract starch and glycogen, which are measured separately.¹²

A 2025 trial paper states that lion's mane mycelium preparations are not allowed in foods or supplements in the EU and UK, while fruiting body extracts are.⁶

Lion's mane as a food

Lion's mane is an edible mushroom found most in East Asia, where it has long been eaten as a food. Fresh fruiting bodies are cooked, sometimes as mushroom steaks of up to 300 g.^4,6

Among seven common mushrooms analysed fresh and raw, lion's mane and oyster mushrooms had the most ergothioneine, an amino acid that plants and animals do not make.¹³

Eating the mushroom is not the same as what the trials tested. They used dried powder or extract in measured daily amounts, taken for weeks.^1,6

What's in ours

Our Lion's Mane gives 1,000 mg a day of fruiting body and mycelium powder, in proportions the label does not state. Mushroom Complex gives 266 mg of lion's mane. Both are well below the roughly 3 g a day of fruiting body powder in the trials above, so we make no claim for either product.^1,2

Side effects, and who should ask first

Stomach discomfort, nausea or diarrhea, reported by under 10% of people in longer trials.^4,11

Skin rash. In a 49-week trial, 3 people taking lion's mane stopped because of stomach discomfort, nausea or a rash, against 1 on placebo who stopped because of nausea.¹¹

Rare: a severe immune reaction in the lungs. A 63-year-old man in Japan developed acute respiratory distress syndrome that doctors linked to a lion's mane extract he had been taking. Tests showed a strong reaction to the extract, and he recovered with steroid treatment on a ventilator.¹⁴

No upper limit is set. Trials have used up to 10 g a day for 4 weeks in young adults, and about 3 g a day for 16 weeks in older adults, where laboratory tests showed no adverse effect. NIH's LiverTox rates lion's mane an unlikely cause of liver injury. Daily use beyond a few months has been studied only in older adults under medical care.^1,3,4,11

Do not take it if you have had an allergic reaction to lion's mane or another mushroom
Ask your doctor first if you are pregnant or breastfeeding: we found no human safety studies
Ask first if you take a blood thinner or antiplatelet medicine, or have surgery planned¹⁵
Ask first if you are under 18, or take prescription medicines every day
If your memory or thinking is getting noticeably worse, see a doctor rather than relying on a supplement

The official sources we use, from NIH, DailyMed and MedlinePlus, do not name a medicine that interacts with lion's mane. That is not the same as proof that it mixes well with every medicine. A compound from the mushroom slowed platelet clumping in laboratory tests, so tell your doctor or pharmacist that you take it.¹⁵

Questions people ask

What does lion's mane do for the body?

It is a food mushroom first. As a supplement, the best human evidence is two small trials in adults over 50 that found slightly higher test scores at about 3 g a day. The nerve growth effects often mentioned come from cell and animal studies and have not been shown to any great extent in people.^1,2,4

Does lion's mane do anything specific for men?

No effect specific to men has been reported. None of the trials we read gave a result for men alone, and the larger ones enrolled both men and women.^1,9,11

Does it matter whether a product uses fruiting body or mycelium?

It matters when you compare a product with the research. The fruiting body supplies hericenones and the mycelium supplies erinacines, and the trials with positive results in adults over 50 used fruiting body powder. A label that lists both parts without amounts cannot be matched to those trials.^1,2,5

Is lion's mane safe to eat?

As a food mushroom it has a long history of use, and NIH's LiverTox rates it an unlikely cause of liver injury. Allergic reactions can happen, including one severe lung reaction to an extract, so avoid it if mushrooms have ever caused you a reaction.^4,14

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Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.