Lion’s Mane human research: what has actually been studied?

If you have ever seen Lion’s Mane growing, the name makes perfect sense. It does not really look like the mushroom most people have in their head. There is no cap, no obvious stalk and no gills underneath. Instead you get this white mass covered in long hanging spines, a bit like a frozen waterfall, a pom-pom, a beard, a hedgehog depending on which country named it.

The Chinese call it houtougu, monkey head mushroom. In Japan it is yamabushitake, named after the yamabushi mountain ascetics and the pom-poms they wore. In Britain it has also been called the bearded tooth fungus or hedgehog fungus. People clearly looked at it and reached for whatever hairy thing was nearest.

It belongs to the genus Hericium, a group of fungi that grow on wood and carry their spore-producing surface on teeth or spines rather than gills. Lion’s Mane itself is normally written as Hericium erinaceus, although even that has become a little more complicated recently. We will get to that because apparently no mushroom research page is allowed to keep the same species name all the way through.

The white fruiting body is only the reproductive part of the organism. Most of the fungus is mycelium growing through the wood. I have grown Lion’s Mane myself and it is one of the reasons I became so interested in fungi in the first place. The mushroom can look almost ridiculous when it fruits properly, white tendrils hanging everywhere, and then you cut it off and the organism that made it is still sitting there in the substrate.

It is a wood-rotting fungus, living on hardwood and doing what fungi have been doing very successfully for rather longer than we have been around. It breaks the wood down, takes what it needs, fruits when the conditions suit it, releases spores and carries on.

Nothing particularly mystical required.

The strange bit comes later.

Which Lion’s Mane?

For years the name Hericium erinaceus was used fairly happily for Lion’s Mane found across Europe, Asia and North America.

Then somebody sequenced them properly.

A four-gene phylogeny published in 2025 looked at the genus using ITS, LSU, TEF-1α and RPB2 sequences and found that some of the Lion’s Mane mushrooms being given the same name were actually separate species. Under that work, Hericium erinaceus itself is European. East Asian material previously called H. erinaceus falls under Hericium asiaticum, eastern North American material under H. carolinense, and western North American material includes the newly described H. oregonense.

This matters rather more than it might first appear because a decent amount of the human research on Lion’s Mane has been done in Japan, Taiwan and China.

Those papers say Hericium erinaceus. That was the name the researchers were using. It does not follow that the fungus they tested would still be called H. erinaceus under the newer taxonomy.

Again, this does not suddenly make the research disappear. A Japanese Lion’s Mane study is still a study of the mushroom material they called Lion’s Mane. But if we are going to get fussy about whether something was a fruiting body or mycelium extract, which we should, it seems slightly odd not to care what species it actually was.

Our research library therefore keeps two things separate. We record the name the paper gives us, because rewriting an old study to suit current taxonomy would be ridiculous, and separately record how confident we can be about the modern species identity.

At the moment the 16 human studies split into six where the reported H. erinaceus name is consistent with European material, and ten where the identity remains unresolved under the newer taxonomy. Even the six European ones are reported-name matches rather than genetic confirmations. None of the human studies in the corpus gives us a modern voucher, sequence or deposited strain that settles the question completely.

This sounds like a nuisance, and it is, but I quite like taxonomy for exactly this reason. We give nature a name, become comfortable with it for a hundred years and then somebody points out that nature has been ignoring us the whole time.

Lion’s Mane in Britain

There is another odd thing about this mushroom if you are reading this in Britain.

You can buy Lion’s Mane supplements everywhere. You can buy grow kits. You can grow it at home. Ours is cultivated in Wales.

The wild British fungus, however, is protected.

Lion’s Mane appears under the older spelling Hericium erinaceum in Schedule 8 of the Wildlife and Countryside Act 1981. There are only four fungi on that protected list: Royal Bolete, Hedgehog Fungus, Oak Polypore and Sandy Stilt Puffball.

So if you are lucky enough to find wild Lion’s Mane growing on a tree here, leave it there.

Its protected status does not mean Lion’s Mane products are made from illegally picked British mushrooms, obviously. Commercial material is cultivated. I only mention it because there is something slightly wonderful about being able to buy a mushroom growing kit for a fungus that would be quite a serious thing to wander into a British woodland and pick.

It also tells us something about its ecology. True H. erinaceus, as now understood, is a European wood-inhabiting fungus and not simply an exotic “Chinese medicinal mushroom” that appeared on supplement shelves one morning.

And unlike Reishi, you can actually eat this one

This is where Lion’s Mane and Reishi part company quite dramatically.

Reishi is woody and bitter. Lion’s Mane is food.

It has been eaten in East Asia for a long time and is valued for its texture and savoury flavour. Fresh Lion’s Mane pulls apart into strands and has that slightly seafood-like quality people are always comparing with crab or lobster. Some of that flavour can actually be traced to glutamic and aspartic acids and specific umami peptides, so there is chemistry behind the culinary description rather than everybody collectively imagining shellfish.

Researchers have now gone much further than merely saying it tastes meaty. One 2026 study actually measured the mechanical properties of Lion’s Mane as a whole-cut meat alternative and then asked people to compare it with animal and plant-based meats. It came out more fatty, fibrous, moist and meaty than the comparison foods.

We have apparently reached the point where mushrooms require engineering data before we are permitted to fry them.

It is also being put into bread, dough and oat-based foods. This side of Lion’s Mane gets slightly lost because the supplement industry is so interested in cognition, but it is worth remembering that for a lot of its history this has simply been a good edible mushroom.

Food and medicine have always overlapped in traditional cultures anyway. Our modern need to decide whether something belongs in the vegetable aisle or the pharmacy is not necessarily a distinction everybody else has shared.

What about the traditional use?

This part is much thinner than Reishi.

You will see plenty of websites confidently telling you that Lion’s Mane has been used in Chinese medicine for centuries for memory, the brain, nerves, digestion and probably whatever else the page is trying to sell that week.

The source material we have does not support telling that story quite so neatly.

A modern ethnopharmacological review describes Hericium species as having a long history as food and traditional medicine in China, India, Japan and Korea. It records the Chinese name houtougu and the Japanese yamabushitake and describes traditional uses around dyspepsia, insomnia, chronic gastritis and digestive complaints.

India is worth pausing on because modern mushroom writing has a habit of turning any Indian traditional use into “Ayurveda”. That may eventually be supportable for Lion’s Mane, but it is not supportable from the material we have in hand. We do not currently have a named classical Ayurvedic text, passage and translation that we can confidently connect to modern Hericium. So India stays in the history, Ayurveda stays an open research question, and we do not fill the gap because it would make a nicer story.

The same goes for China and Japan. Houtougu and yamabushitake are real names with a real history, but a historical name is not a DNA sequence. The older the source, the more careful we need to be about pretending the modern species name travelled back in time with it.

What is interesting is what is not particularly prominent there.

Cognition.

The modern Lion’s Mane story is overwhelmingly about the brain. The traditional material we have found is much more gastrointestinal.

That surprised me because I had absorbed exactly the same story everybody else had, that Lion’s Mane had always been some ancient brain mushroom and modern researchers had eventually turned up and confirmed why.

It seems the story may have run the other way.

The proper historical work is still thin. At the moment we have a scholarly review of the ethnopharmacology, not a named old Chinese text sitting in front of us with a chapter and translation we can inspect. There is also the species problem again. Houtougu in historical East Asia cannot simply be assumed to mean the European species now called Hericium erinaceus.

So for now I would rather say we do not know enough than invent several hundred years of beautifully convenient neuroscience.

Homeopathy is another interesting omission. In my 2022 dissertation I went looking specifically for fungal remedies and found Lion’s Mane barely represented at all. The better-developed homeopathic fungal literature centres on things such as Agaricus, Bovista and Claviceps, with Cordyceps appearing much more clearly than Lion’s Mane. Reishi, Chaga, Turkey Tail, Maitake, Shiitake and Lion’s Mane were, in practical terms, almost missing from the sources I reviewed.

Again, that is not efficacy evidence. It is a record of what that tradition paid attention to and what it did not. I think that belongs here because the history of a mushroom is not only the history that later turned out to fit a clinical endpoint.

Fortunately, we do know rather more about where the modern brain story came from.

Hericenones, erinacines and why anybody started looking at the brain

This is the bit I find fascinating.

In 1991, Hirokazu Kawagishi and colleagues in Japan isolated compounds from Lion’s Mane fruiting bodies that they called hericenones. Some of those compounds stimulated nerve growth factor synthesis in cultured cells.

Then in 1994 the same research group reported another family of compounds from Lion’s Mane mycelium, the erinacines, again with strong nerve growth factor stimulating activity in laboratory experiments.

That is basically where the modern neurological Lion’s Mane story begins.

Not with somebody in ancient China saying it improves memory. Not with somebody taking a capsule and suddenly remembering where they left the car keys. With chemists extracting compounds from a fungus and seeing something interesting happen in cells.

And there is a useful distinction hidden in there which gets lost constantly online.

Hericenones came from the fruiting body. Erinacines came from the mycelium.

You will regularly see the two words thrown together in descriptions of Lion’s Mane as though every product naturally contains both in useful quantities. That is not what the chemistry says.

Hericenones were isolated from less water-soluble fractions of the fruiting body. Erinacines are associated with mycelium and fermentation, and even there the amount produced changes enormously according to the strain and how the mycelium is grown. A 2025 fermentation study showed just how dramatically culture conditions could alter erinacine production.

So fruiting body versus mycelium genuinely matters here. This is not somebody arguing about whether the potato was mashed or roasted. You are looking at different parts of the fungal organism containing different compound families.

Grym Lion’s Mane uses fruiting body.

That means hericenones are directly relevant to discussing its chemistry. Erinacines are interesting Lion’s Mane research, and important to understanding why several clinical studies deliberately used mycelium, but they are not something we should quietly imply is in our fruiting-body extract.

There are many other compounds in Lion’s Mane too. Beta-glucans, phenolics, ergothioneine and a growing catalogue of secondary metabolites. One review of the genus lists 230 secondary metabolites across six structural classes. Fungi do chemistry extremely well.

The hericenone and erinacine work caught everybody’s attention because nerve growth factor is involved in the growth, maintenance and survival of certain neurons. Once you have a mushroom compound doing something around NGF in a laboratory, you can probably guess what researchers did next.

Cells became animals. Animals became small human trials. Cognition, mood, dementia, stress, hearing, sleep and various other things started appearing in the literature.

And this is where the story gets considerably messier than the supplement version of Lion’s Mane would have you believe.

What happened in cells and animals?

Quite a lot, which is probably why Lion’s Mane acquired such a confident reputation before the human evidence had really caught up.

There are cell studies showing effects around nerve growth factor. There are animal studies involving nerve injury, ageing, learning, metabolic dysfunction, inflammation and various models of neurodegeneration. An aqueous fruiting-body extract has been studied in rats after peripheral nerve injury. Erinacine A enriched mycelium has been studied in ageing mice. Polysaccharides have been looked at in gut and inflammatory models, including primates.

If you read only this part of the literature it is very easy to become enthusiastic.

I am enthusiastic. That is not quite the same thing.

A compound making a nerve cell produce more NGF is interesting. A mouse performing differently in a maze is interesting. A rat recovering differently after a crushed peripheral nerve is interesting. These are exactly the sort of findings that justify asking whether the mushroom might do something useful in people.

They are not the answer to that question.

This distinction gets particularly muddled with Lion’s Mane because words such as “nerve growth”, “neurogenesis” and “neuroprotective” sound wonderfully close to a human outcome. They are not. The animal and cell work gives us a biological story, perhaps even a very plausible one, but the next step is still to give the material to people and compare what happens.

Fortunately people have done that too.

The human studies

We currently have 16 verified human primary studies in the Lion’s Mane library, involving 638 participants. Twelve were placebo-controlled, involving 407 people.

That sounds like quite a lot until you spread those people across cognition, mood, sleep, hearing, gut microbiota, metabolic measures, Helicobacter pylori, healthy young adults, older adults and several different preparations of the mushroom. Suddenly 638 people does not feel quite so enormous.

Using the same rules across the whole corpus, three studies come out positive, six mixed, three null, one unresolved from the source we have, and three were not really efficacy studies in the first place.

There are no negative efficacy studies in the corpus. There are also nowhere near enough clean positive ones to justify the certainty you will find attached to Lion’s Mane online.

The best-known early trial was published in Japan in 2009. Thirty people with mild cognitive impairment were randomised to Lion’s Mane or placebo for sixteen weeks. The Lion’s Mane group performed better on the study’s cognitive scale while taking it. This is a genuinely positive placebo-controlled trial and it deserves to be in the conversation.

It is also thirty people.

A year later another Japanese study looked at menopausal and other non-specific complaints. The title says Lion’s Mane reduced depression and anxiety, which sounds wonderfully straightforward. The actual between-group results are not. Two subscales of an “Indefinite Complaints” index differed, while the depression scale, sleep score, menopausal index and several other measures did not. The depression improvement highlighted in the paper was within the Lion’s Mane group rather than a clean difference from placebo.

That one is mixed.

In 2019 a study of people with overweight or obesity reported improvements in mood and sleep. Again, the title is much stronger than the between-group data. The comparisons between the Lion’s Mane and control groups were null, while the positive changes were largely changes within the Lion’s Mane group over time.

That one is null.

This is becoming a bit of a theme.

A 2020 pilot study used erinacine A enriched mycelium in people with mild Alzheimer’s disease for almost a year. Some outcomes moved, including instrumental activities of daily living and one contrast-sensitivity measure. MMSE, the cognitive score most people will recognise, did not differ between groups even though the abstract highlights an improvement within the treatment group.

Mixed.

A 2022 study in people with hearing impairment found no significant whole-group differences in hearing measures, NGF or BDNF, but reported positive results in a subgroup aged 65 and over. Interesting, but a subgroup is not the whole trial.

Mixed again.

Then there are some very clean nulls. In 2022, 24 people consumed 10 g of Lion’s Mane a day in muffins for four weeks and showed no difference from placebo in cognition or metabolic flexibility. In 2023, 40 healthy adults took a single dose of fruiting body and were tested on several cognitive tasks. The abstract describes improvements from baseline, but Lion’s Mane did not beat placebo on the relevant comparisons.

That distinction matters enormously. If both groups improve because they have seen the test before, then “people improved after taking Lion’s Mane” can be true whilst “Lion’s Mane improved performance” is not.

A 2023 trial in young adults is another good example. The declared overall cognitive outcomes were null after 28 days, but there were differences on a Stroop measure after a single dose and on a subjective stress measure later on. Again, interesting, but mixed.

A small 2024 pilot of erinacine-enriched mycelium reported an adjusted difference on two non-verbal speed tests, while several biomarkers did not differ. A 2025 crossover trial in 18 healthy adults found no difference on its overall cognitive composite but did find a difference on a secondary pegboard task.

And then in 2026 a larger study, 109 analysed participants, reported positive differences in visual attention and working memory, subjective sleep quality, morning restedness and mood after eight weeks. That is worth paying attention to. It used a combination of fruiting body and mycelial biomass rather than a fruiting-body extract, and it had commercial involvement, neither of which makes the result invalid. They simply tell you what was actually tested and who was involved.

So where does that leave us?

Somewhere much less exciting than “Lion’s Mane is proven to improve memory”, but also much more interesting than “there is no evidence”.

There are real human trials. Some are positive. Some are mixed. Some are null. A lot of them are small. Several use mycelium or mixed material rather than fruiting body. Different studies test different outcomes, different populations, different amounts and different preparations. Some of the strongest-sounding claims disappear when you stop looking at changes within one group and ask whether Lion’s Mane actually beat the control.

That is the research as it stands.

The reviews do not rescue it

Once enough small studies exist, somebody eventually writes a review and tries to make the whole thing behave.

We have three systematic reviews in the current library.

A 2023 review of mental-health studies found only three Japanese randomised controlled trials. It considered the cognitive findings potentially interesting but did not find support for depression or anxiety. The authors themselves called for longer studies outside Japan.

A 2025 systematic review sounds much larger because it included 26 records, but only eight were human studies. The rest included laboratory work, pilot studies, a case report and computer analysis. It also combined an MMSE change from a randomised study with an uncontrolled pilot study, which is not a comparison I would lean very heavily on.

A 2026 systematic review included 23 studies and described broadly positive neuroprotective findings. Twenty of those 23 studies were cell or animal work. Three were human trials. The authors themselves concluded that heterogeneity and limited clinical evidence prevented firm conclusions.

That pretty much sums up the problem.

Lion’s Mane has a strong preclinical story and an interesting human one. The two are often presented as though they are the same body of evidence. They are not.

Safety

Most human Lion’s Mane studies are small and relatively short, so the absence of lots of adverse events in them should not be mistaken for an enormous safety database.

There are a few case reports and allergy reports worth knowing about.

The most serious Lion’s Mane-specific report we found is from 2003. A 63-year-old man developed acute respiratory distress after taking a commercial Hericium extract. The report included laboratory evidence of an immune reaction to the product and the patient required mechanical ventilation before recovering.

That is one case. It is serious, and it is still one case.

There is also an occupational contact-dermatitis report from handling fresh Lion’s Mane and a 2022 conference report of anaphylaxis after eating it. The latter is only available to us as meeting metadata, so there is not enough detail to say much more than that the report exists.

A 2025 liver-injury case sometimes appears in searches around Lion’s Mane, but the supplement contained both Agaricus blazei and Lion’s Mane and the authors themselves attributed the problem to Agaricus. Calling that a Lion’s Mane liver-injury case would be wrong, so we do not.

Case reports are useful because they tell you what has happened. They do not tell you how likely it is to happen.

How close is any of this to Grym Lion’s Mane?

Grym Lion’s Mane is a fruiting-body liquid extract made with hot water and alcohol. The mushroom is grown and extracted in Wales.

None of the 16 verified human studies tested that exact preparation.

That does not make all 16 studies irrelevant. It means you have to look at how close each one is.

Some studies used fruiting body, some mycelium, some both, and several do not give us enough detail to know. Some used powder, some capsules, some food and some enriched mycelium preparations designed specifically around erinacine A. Nine of the 16 do not have enough extraction information for a detailed comparison. Seven are materially different from our product because the part or preparation is different.

The important distinction is not “identical or useless”. Research does not work like that.

A fruiting-body study is relevant to a fruiting-body product even if the preparation differs. A mycelium study is still relevant to understanding Lion’s Mane research, but less direct for a product containing no mycelium. An erinacine-enriched mycelial preparation tells us something interesting about erinacines and very little about the hericenone content of our bottle.

And species uncertainty sits over all of it.

The product is labelled Hericium erinaceus. The modern taxonomy now gives that name a narrower European meaning. Six trials are at least consistent with that reported identity, ten remain unresolved, and none gives us a modern genetic identification that closes the matter.

That is not a reason to throw the research away. It is a reason to stop pretending it is tidier than it is.

So, does Lion’s Mane work?

This is probably the question most people came here for, and I am afraid the answer is not going to fit on a label.

There is human evidence. It is not all anecdotal. There are placebo-controlled trials and some of them report positive findings. But the confidence surrounding Lion’s Mane in popular culture is much bigger than the clinical evidence supporting it.

A lot of what people think they know comes from animal work, cell studies, mechanistic theories, personal experience, podcasts, supplement marketing and other people saying they felt sharper, calmer, slept better or remembered more. Some of those people may be absolutely right about what they experienced. Anecdote is how humans notice things in the first place. It is just very bad at telling us what caused them.

The formal research is hardly glorious either. Small studies, different materials, different species identities, mixed endpoints, subgroup findings, within-group results presented more enthusiastically than the controls justify, and a tendency for the same handful of trials to be recycled through reviews until the literature looks bigger than it is.

So yes, viewed purely as proof of efficacy, it is all a bit terrible.

But I do not think that makes Lion’s Mane less interesting.

It is a protected British fungus, a genuinely good food, a strange and beautiful organism, a wood recycler, a source of unusual chemistry and the reason chemists have spent more than thirty years pulling apart hericenones and erinacines. There is enough going on here to keep studying it for another thirty years without having to pretend we already know the answer.

You also do not need a p-value before you are allowed to like a mushroom.

Grow it. Cook it. Read about it. Take an interest in the chemistry. If you choose to use it as a food supplement, fine. Just keep the two thoughts in your head at the same time: people report all sorts of things from Lion’s Mane, and the clinical evidence has not yet proved most of them.

Mushrooms remain brilliant either way.

Still unresolved

There are some very obvious questions left.

Which species were actually used in the East Asian trials? Does fruiting body behave differently from mycelium in people, rather than merely in a chemistry paper? Do hericenones or erinacines reach meaningful concentrations in the human body? Is there a useful dose-response relationship? Does longer use matter? What happens when a proper fruiting-body liquid extract is tested rather than powders, foods and enriched mycelium preparations?

At the moment nobody can answer those questions cleanly from the verified human literature.

Good.

There is still something left to find out.

The complete Lion’s Mane research library

Research last searched: 3 October 2026

The current library contains 16 verified human primary studies involving 638 participants, including 12 placebo-controlled studies involving 407 people. It also contains three systematic reviews, selected preclinical work, five safety records and the historical material we could verify without filling gaps with folklore.

The full tables below keep the positive, mixed, null and unresolved findings together. They also keep cell work, animal work, historical use and human trials visibly separate, because otherwise the whole subject becomes much more certain than it really is.

References