Lion's Mane Mushroom: Nootropic or Hype?

Short answer: Unproven. Lion’s mane raises nerve growth factor in cell and animal studies. Three small trials in older adults found gains on some cognitive tests, but none was large or independently replicated. Two trials used about 3 g a day of dried mushroom powder. Many products are mostly grain. Ask a doctor first if you take blood thinners.

Lion’s mane is unproven, but it is not pure marketing either. The evidence is preliminary. Its compounds stimulate nerve growth factor in the lab. Three small trials in Japan and Taiwan reported better scores on some cognitive tests in older adults, while other tests in the same trials did not change.

If you want to try it, note what the trials used: dried fruiting-body powder (about 3 g a day) or a specific erinacine-enriched mycelium (about 1 g a day). They lasted 12 to 49 weeks. Choose a product that states its source material and has third-party testing, and expect a slow effect, if any.

What lion’s mane is

Lion’s mane (Hericium erinaceus) is a large, white, shaggy mushroom with cascading spines that grows on hardwood trees in North America, Europe and Asia. It has been used in traditional Chinese and Japanese medicine for centuries, mainly for digestion and general vitality. Cooked fresh, it has a mild, slightly sweet taste often compared to lobster or crab.

Its brain reputation rests on two groups of compounds:

• Hericenones, found mainly in the fruiting body (the visible mushroom). Kawagishi (1991) isolated hericenones C, D and E and reported that they stimulated nerve growth factor in cell culture. A later study found that these three did not increase nerve growth factor gene activity in human astrocytoma (brain tumor) cells, although whole lion’s mane extract did (Mori 2008).
• Erinacines, found mainly in the mycelium, the root-like network that grows through the material the fungus feeds on. Erinacines A, B and C were described as strong stimulators of nerve growth factor in cell studies (Kawagishi 1994), followed by E, F and G (Kawagishi 1996).

Which compounds matter in people is not known.

Why nerve growth factor matters

Nerve growth factor (NGF) is a protein that helps neurons survive, grow and connect. Its discoverers, Rita Levi-Montalcini and Stanley Cohen, shared the 1986 Nobel Prize in Physiology or Medicine. NGF is especially important for the acetylcholine-making neurons at the base of the brain, the cells hit hardest in Alzheimer’s disease. It supports the growth of nerve fibers, their insulating myelin, and the strengthening of connections that underlies learning.

The idea behind lion’s mane is that raising NGF might help protect neurons. This has not been shown in people, and no trial has measured NGF in the human brain after taking it.

What the human trials show

Mori 2009: mild cognitive impairment

In a double-blind trial (Mori 2009), 30 Japanese adults aged 50 to 80 with mild cognitive impairment took lion’s mane tablets or a placebo for 16 weeks. The tablets were 96 percent dried lion’s mane powder, 3 g a day in total. Thinking was measured with a scale based on a Japanese dementia screening test.

The lion’s mane group improved more than placebo at weeks 8, 12 and 16, and scores kept rising through the trial. Four weeks after stopping, their scores fell back toward baseline, which suggests any benefit needs continued use.

The trial was small, in one population, and used a screening test rather than a full set of cognitive tests. No independent group has fully replicated it.

Saitsu 2019: healthy older adults

Saitsu (2019) ran a double-blind, placebo-controlled trial in healthy Japanese adults over 50, with 31 analyzed. They took 3.2 g a day of powdered fruiting body (four 0.8 g supplements) or placebo for 12 weeks. Of three tests, only the MMSE, a standard memory and thinking test, improved. A visual memory test and a verbal learning test did not.

Li 2020: mild Alzheimer’s disease

Li (2020) ran a 49-week double-blind pilot trial of an erinacine A-enriched mycelium (5 mg erinacine A per gram) in people with mild Alzheimer’s disease. Of 49 randomized, 41 completed it. The treatment group took three 350 mg capsules a day.

Scores on one cognitive scale (CASI) fell in the placebo group, and MMSE scores improved in the treatment group. Scores for daily activities differed between groups, as did some brain-imaging measures. Four people dropped out because of stomach discomfort, nausea or skin rash. The sample was small, the corresponding author worked for the company that makes the preparation, and that preparation is not widely available in consumer products.

Putting the trials together

• Three small randomized trials reported better scores on some cognitive tests in older adults with mild cognitive impairment, mild Alzheimer’s disease or no impairment. Other tests in the same trials did not change.
• Whether the changes are large enough to matter in daily life is unclear.
• Benefits seem to need ongoing use; in Mori, they faded after stopping.
• All were in Japan or Taiwan, with about 30-50 participants, and some were run by product makers.
• No large, multi-site trial has been done.

This puts lion’s mane ahead of supplements that rely only on lab data, but short of what is needed for a clinical recommendation. It is not a treatment for dementia; memory problems should be discussed with a doctor.

Animal and cell studies

• NGF in mice: Mice fed 5 percent dried lion’s mane fruiting body for 7 days had higher NGF gene activity in the hippocampus, the memory center; no memory tests were run (Mori 2008).
• Memory in mice: Lion’s mane improved recognition memory in healthy mice and increased signaling between hippocampal neurons (Brandalise 2017).
• Alzheimer’s-model mice: An erinacine A-enriched mycelium promoted new neurons in the hippocampus. Thirty days of it reduced amyloid plaque burden and the number of plaque-activated glial (support) cells, and raised the ratio of NGF to its precursor (Tsai-Teng 2016).
• Myelin: In cultured cerebellar cells, lion’s mane extract made myelination start earlier and proceed faster (Kolotushkina 2003). Whether it affects myelin in people is unknown.
• Nerve cells: Compounds from the mycelium, including erinacine A, protected nerve-like cells and enhanced NGF-driven fiber growth (Zhang 2017).

Many compounds that looked good in rodents have failed in human trials, so lion’s mane should be held to the same standard as any other treatment.

How to choose a lion’s mane supplement

Mushroom supplements vary widely, and label claims often don’t match what is inside.

Fruiting body or mycelium on grain

Fruiting body products are made from the mushroom itself and contain hericenones, beta-glucans and other compounds. Two of the three positive trials used fruiting-body powder.

Mycelium-on-grain products are made by growing the fungus on sterilized rice or oats. The mycelium can’t be fully separated from the grain at harvest, so part of the product can be grain starch, which adds nothing. You may get a fraction of the active compounds the milligram count suggests.

Mycelium is not automatically worse, because erinacines are found mainly in the mycelium. But the mycelium should be grown in liquid culture rather than on grain, with erinacine content verified by third-party testing. The Li trial used an erinacine A-enriched preparation made under controlled conditions, very different from a mass-market mycelium-on-grain product. No trial has compared fruiting body with mycelium.

Extracts and powders

Products come as dried powders or extracts. Fungal cell walls are made of chitin, which human digestion breaks down poorly. Hot water extraction releases beta-glucans and hericenones; alcohol extraction captures other compounds, such as some terpenes and sterols; dual extraction combines both and is popular in the industry.

But the positive trials used dried powder (Mori, Saitsu) or a specific mycelium (Li), not extracts, and no trial has compared extraction methods.

What to look for on the label

• Source material: fruiting body, mycelium or both.
• Beta-glucan content as a percentage, which helps separate fungal material from grain filler.
• Starch content disclosed or tested; a high figure means a grain-heavy product.
• Extraction method: hot water, alcohol or dual.
• Third-party testing for purity, potency and contaminants.

Treat products that list only total milligrams with skepticism.

Doses used in trials

These are research doses, not recommendations, and commercial products differ from those tested. No study has looked at timing. Lion’s mane has no quick, noticeable effect; in Mori, differences from placebo appeared from week 8, so allow at least two to three months before judging it.

Eating the fresh mushroom is fine, and beta-glucans are fairly heat-stable. But a culinary serving contains much less hericenone and erinacine than the trial doses.

Safety

Lion’s mane has long been eaten as a food in East Asia, and no serious adverse effects were reported in the small trials. Lab tests showed no adverse effects in the Mori trial. In the 49-week Li trial, four of 49 participants dropped out because of stomach discomfort, nausea or skin rash. There are no multi-year safety studies.

• Stomach upset: Some people report mild discomfort, especially at higher doses or on an empty stomach. Taking it with food or lowering the dose usually helps.
• Allergy: Skin rash occurred in the Li trial, and mushroom allergies happen. Anyone allergic to mushrooms should avoid lion’s mane.
• Blood thinners and other medicines: Interactions have not been studied in people. Lion’s mane has been proposed to affect platelets, so people taking blood thinners (warfarin, aspirin, clopidogrel) should ask their doctor first. Talk to your doctor too if you take immunosuppressants or any medication that could interact with a supplement affecting platelets or the immune system. Ask a doctor or pharmacist before starting if you take medication or have a health condition.
• Pregnancy and breastfeeding: There are not enough safety data, so avoiding it is the prudent default.

How it compares with better-studied supplements

• Omega-3s (DHA and EPA) have many more trials, including large ones, though their effects on cognition in people without dementia are small or absent.
• Creatine has more randomized trials and a meta-analysis showing a small memory benefit, mainly in older adults.
• Citicoline has a Cochrane review of short trials in older people with cognitive impairment.

Lion’s mane has fewer and smaller trials than any of these. Its trials have been positive so far, but they have not faced large-scale testing, which has turned many promising supplements null. None of these is proven to improve cognition in healthy people. Our guide to brain health supplements covers more options.

Frequently Asked Questions

Can I take lion’s mane with other nootropics?

Interactions with other supplements or medicines have not been studied. Don’t add compounds without a specific reason, and ask a doctor or pharmacist if you take medication.

Does lion’s mane cure brain fog or regrow neurons?

No. Those claims go well beyond the evidence. Small trials suggest it may modestly improve some cognitive test scores in older adults, and that is all that has been shown in people.

Sources

• Kawagishi, H., Ando, M., Sakamoto, H., Yoshida, S., Ojima, F., Ishiguro, Y., Ukai, N., & Furukawa, S. (1991). Hericenones C, D and E, stimulators of nerve growth factor (NGF)-synthesis, from the mushroom Hericium erinaceum. Tetrahedron Letters, 32(35), 4561–4564. doi:10.1016/0040-4039(91)80039-9

• Kawagishi, H., Shimada, A., Shirai, R., Okamoto, K., Ojima, F., Sakamoto, H., Ishiguro, Y., & Furukawa, S. (1994). Erinacines A, B and C, strong stimulators of nerve growth factor (NGF)-synthesis, from the mycelia of Hericium erinaceum. Tetrahedron Letters, 35(10), 1569–1572. doi:10.1016/s0040-4039(00)76760-8

• Kawagishi, H., Shimada, A., Hosokawa, S., Mori, H., Sakamoto, H., Ishiguro, Y., … & Furukawa, S. (1996). Erinacines E, F, and G, stimulators of nerve growth factor (NGF)-synthesis, from the mycelia of Hericium erinaceum. Tetrahedron Letters, 37(41), 7399–7402. doi:10.1016/0040-4039(96)01687-5

• Mori, K., Obara, Y., Hirota, M., Azumi, Y., Kinugasa, S., Inatomi, S., & Nakahata, N. (2008). Nerve growth factor-inducing activity of Hericium erinaceus in 1321N1 human astrocytoma cells. Biological and Pharmaceutical Bulletin, 31(9), 1727–1732. doi:10.1248/bpb.31.1727

• Mori, K., Inatomi, S., Ouchi, K., Azumi, Y., & Tuchida, T. (2009). Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: A double-blind placebo-controlled clinical trial. Phytotherapy Research, 23(3), 367–372. doi:10.1002/ptr.2634

• Saitsu, Y., Nishide, A., Kikushima, K., Shimizu, K., & Ohnuki, K. (2019). Improvement of cognitive functions by oral intake of Hericium erinaceus. Biomedical Research, 40(4), 125–131. doi:10.2220/biomedres.40.125

• Li, I. C., Chang, H. H., Lin, C. H., Chen, W. P., Lu, T. H., Lee, L. Y., Chen, Y. W., Chen, Y. P., Chen, C. C., & Lin, D. P. (2020). Prevention of early Alzheimer’s disease by erinacine A-enriched Hericium erinaceus mycelia pilot double-blind placebo-controlled study. Frontiers in Aging Neuroscience, 12, 155. doi:10.3389/fnagi.2020.00155

• Brandalise, F., Cesaroni, V., Gregori, A., Repetti, M., Romano, C., Orrù, G., … & Rossi, P. (2017). Dietary supplementation of Hericium erinaceus increases mossy fiber-CA3 hippocampal neurotransmission and recognition memory in wild-type mice. Evidence-Based Complementary and Alternative Medicine, 2017, 3864340. doi:10.1155/2017/3864340

• Kolotushkina, E. V., Moldavan, M. G., Voronin, K. Y., & Skibo, G. G. (2003). The influence of Hericium erinaceus extract on myelination process in vitro. Fiziolohichnyi Zhurnal, 49(1), 38–45. PMID:12675022

• Tsai-Teng, T., Chin-Chu, C., Li-Ya, L., Wan-Ping, C., Chung-Kuang, L., Chien-Chang, S., … & Shiao, Y. J. (2016). Erinacine A-enriched Hericium erinaceus mycelium ameliorates Alzheimer’s disease-related pathologies in APPswe/PS1dE9 transgenic mice. Journal of Biomedical Science, 23(1), 49. doi:10.1186/s12929-016-0266-z

• Zhang, C. C., Cao, C. Y., Kubo, M., Harada, K., Yan, X. T., Fukuyama, Y., & Gao, J. M. (2017). Chemical constituents from Hericium erinaceus promote neuronal survival and potentiate neurite outgrowth via the TrkA/Erk1/2 pathway. International Journal of Molecular Sciences, 18(8), 1659. doi:10.3390/ijms18081659

• Friedman, M. (2015). Chemistry, nutrition, and health-promoting properties of Hericium erinaceus (lion’s mane) mushroom fruiting bodies and mycelia and their bioactive compounds. Journal of Agricultural and Food Chemistry, 63(32), 7108–7123. doi:10.1021/acs.jafc.5b02914

• Chong, P. S., Fung, M. L., Wong, K. H., & Lim, L. W. (2019). Therapeutic potential of Hericium erinaceus for depressive disorder. International Journal of Molecular Sciences, 21(1), 163. doi:10.3390/ijms21010163