Lion's Mane: what the human studies actually say (2026)

Updated 26 September 2026

Lion's Mane has a big reputation and a small evidence base. Ask whether it works and the fair reply is that a handful of human trials found measurable differences on some tests, in some groups, at some doses. Most of those trials were small, and several were run or funded by companies that sell the mushroom.

This article goes through every human trial we could find on PubMed, one by one: who took part, what they took, what changed and what stayed the same. For the background on the mushroom itself, how it grows and how it has been eaten, read our Lion's Mane guide. Here we stick to the studies.

The short answer

Nobody can honestly say Lion's Mane works in the way adverts suggest. The human evidence is narrower than that:

• In older Japanese adults with mild cognitive impairment, 16 weeks of Lion's Mane powder tablets went with higher scores on a cognitive scale than placebo. Scores fell again within four weeks of stopping (Mori, 2009).
• In healthy people over 50, 12 weeks of fruiting body powder went with higher scores on one of three memory tests (Saitsu, 2019).
• In healthy adults aged 18 to 45, a single 1.8g dose was followed by faster times on one attention task. Most other tests showed no difference from placebo (Docherty, 2023).
• In two mood studies, people taking Lion's Mane reported lower scores on depression and anxiety questionnaires. One was tiny and the other wasn't placebo controlled.

No trial has had more than 77 people. The longest ran for 49 weeks, in people who already had Alzheimer's disease. Nobody has yet run the study that would settle the question for healthy adults: a few hundred people, a set dose, several months and a placebo.

How to read a Lion's Mane study

Most articles about Lion's Mane mix three kinds of research without saying which is which. They are not equal.

• Cell studies put compounds from the mushroom onto cells in a dish. They show what a compound can do in the lab, at doses a person may never reach.
• Animal studies usually use mice or rats, often at high doses, sometimes by injection. Results in rodents often fail to carry over to people.
• Human trials are the ones that tell you what happens when a person takes the mushroom. The strongest design is randomised, double blind and placebo controlled, so neither the volunteers nor the researchers know who is taking what.

Two more details matter. A result is usually called significant when there is less than a 5% chance it came from luck alone, and small trials struggle to clear that bar. And some papers compare a group with its own starting scores rather than with the placebo group. People taking a dummy pill often feel better too, so a before and after change is weaker evidence than a gap between the two groups.

Every human trial at a glance

If you're skimming, this table is the whole article in eight rows. The sections after it go trial by trial.

Memory and thinking in older adults

Mori et al., 2009

This is the trial most guides quote. Researchers in Japan recruited men and women aged 50 to 80 who had been diagnosed with mild cognitive impairment. Thirty were split into two groups of 15. One group took four 250mg tablets of dried Lion's Mane powder three times a day, twelve tablets and 3g in total. The other took look-alike placebo tablets.

At weeks 8, 12 and 16, the Lion's Mane group scored higher than the placebo group on a cognitive scale based on the Revised Hasegawa Dementia Scale. Their scores climbed the longer they took it. Four weeks after they stopped, the scores had dropped significantly. Blood tests showed no adverse effects. Why the gap closed so quickly is something the paper doesn't explain, and nobody has tested it since.

A few guides give the daily amount in this trial as 750mg. The paper's abstract describes twelve 250mg tablets a day, which is 3g. The lead researcher worked for Hokuto Corporation, a Japanese mushroom grower.

Saitsu et al., 2019

A later Japanese trial, with two of the Nagano 2010 authors on the team, tested healthy people instead. Thirty four Japanese adults over 50 with normal memory scores were randomised, and 31 were analysed. The Lion's Mane group took four servings a day, each containing 0.8g of powdered fruiting body, for 12 weeks.

They sat three tests. Scores on the Mini Mental State Examination, a 30 point screening test used in memory clinics, were higher in the Lion's Mane group. The Benton visual retention test and a verbal paired word test showed no significant change. One test out of three is a thin result, and the MMSE is a coarse tool for people whose memory is already normal.

Li et al., 2020

This Taiwanese trial is the longest so far. Forty nine people with mild Alzheimer's disease were randomised and 41 finished. The active group took three 350mg capsules a day of Lion's Mane mycelium grown to contain more erinacine A, one of the compounds studied in the lab. The trial ran for 49 weeks.

Over that time, scores on one cognitive screening test fell in the placebo group, while the Lion's Mane group's MMSE scores went up. The groups also differed on a scale of everyday activities, such as managing money or using the phone. Four people dropped out with stomach discomfort, nausea or a skin rash.

The study was run by Grape King Bio, which makes the capsules. It used mycelium, not the fruiting body most supplements are made from. And it was in people with a diagnosed disease, so it says nothing about healthy adults. No food supplement in the UK can claim to treat or prevent Alzheimer's.

Focus and speed in younger adults

Docherty et al., 2023

Run at Northumbria University in Newcastle, this pilot is the best designed trial in healthy people. Forty one adults aged 18 to 45 took 1.8g of Lion's Mane or placebo each day. They did memory, attention and mood tests after the first dose and again after 28 days.

Sixty minutes after a single dose, the Lion's Mane group was quicker on the Stroop task, where you name the ink colour of a word while ignoring the word itself. After 28 days there was a trend towards lower stress ratings that just missed significance. Most other measures showed no difference, and a few went slightly the wrong way. The authors asked for larger trials. A supplement company supplied the product but had no part in the analysis.

La Monica et al., 2023

This American crossover trial gave each volunteer three single doses on separate days: 1g of Nordic grown Lion's Mane, a guayusa tea extract, or placebo. After Lion's Mane, some reaction time and working memory scores were better at one and two hours, and people rated themselves happier. The guayusa, which contains caffeine, moved more measures. A single dose tells you little about daily use.

Surendran et al., 2025

A second UK study, from the University of Surrey, gave 18 healthy adults aged 18 to 35 either 3g of a 10:1 fruiting body extract or placebo, on different days. Ninety minutes later there was no difference in overall thinking or mood scores. People did better on one pegboard task only. Two authors worked for a drinks company that uses Lion's Mane.

Mood, stress and sleep

Nagano et al., 2010

Thirty Japanese women ate cookies made with Lion's Mane or placebo cookies for four weeks, around 2g of mushroom a day. They filled in questionnaires on depression, sleep, menopause symptoms and general complaints.

In the Lion's Mane group, depression and general complaint scores were lower at the end than at the start. Against the placebo group, though, only two individual items on the complaints list were significantly lower. Concentration, irritability and anxiety leaned the same way without reaching significance. Guides that say this trial "reduced anxiety" are reading more into it than the numbers allow.

Vigna et al., 2019

In Milan, 77 adults with overweight or obesity, most of them women with an average age of about 53, were all following a low calorie diet. Everyone had at least one mood, sleep or binge eating problem on screening questionnaires. Forty took three capsules a day of a blend that was 80% mycelium and 20% fruiting body extract for eight weeks. Thirty seven formed a control group.

Depression, anxiety and sleep scores fell in the Lion's Mane group. Blood levels of pro-BDNF, a precursor of a protein linked to nerve growth, rose. The paper doesn't describe a placebo capsule or blinding, so people probably knew what they were taking, which matters a lot for self-rated mood.

What a 2025 systematic review found

A systematic review in Frontiers in Nutrition in 2025 pulled together the clinical research published up to June 2024. It found five randomised controlled trials and three pilot trials, plus lab work. Pooling two of the trials, MMSE scores rose by an average of 1.17 points in the Lion's Mane groups. On a 30 point test that is a small shift. The reviewers listed stomach discomfort, headache and allergic reactions as side effects that are often unreported. Their conclusions were upbeat, but they rest on the same small trials listed above.

What the evidence does and does not show

What it shows

• Several small, placebo controlled trials found differences on specific cognitive tests, mostly in people over 50 and mostly after 8 to 16 weeks.
• Where researchers stopped the mushroom and kept testing, as in Mori 2009, the difference faded within weeks.
• Doses of 1g to about 3g a day for up to 49 weeks were well tolerated in these trials, with few dropouts.
• Single doses have produced small changes on one or two tasks, alongside many tasks where nothing changed.

What it doesn't show

• That Lion's Mane changes memory or focus in healthy younger adults over months. The longest trial in that group lasted 28 days.
• That it treats or prevents dementia, depression, anxiety or any other condition.
• Which dose is best, or whether fruiting body, mycelium or a concentrated extract behaves differently. No trial has compared them head to head.
• That results from powder, cookies or erinacine enriched capsules transfer to coffees, drinks or gummies.
• Anything about long term safety beyond a year.

Where the bigger claims come from

Much of what you read about Lion's Mane comes from lab and animal work, not people. It is useful research, and it explains why scientists keep studying the mushroom. None of it tells you what a supplement will do for you.

• Nerve growth. Hericenones, found in the fruiting body, and erinacines, found mainly in the mycelium, raised production of nerve growth factor in cell studies. In rodents, erinacines crossed the blood brain barrier, and rats with nerve injuries recovered faster.
• Blood sugar. Mice and rats given Lion's Mane extracts had lower blood sugar, and one extract blocked an enzyme called alpha glucosidase that breaks down carbohydrate in the gut.
• Stomach. Extracts protected rats against ulcers and slowed the growth of Helicobacter pylori, a bacterium behind many stomach ulcers, in lab tests.
• Heart and blood. A mouse study on a high fat diet reported lower triglycerides. A compound called hericenone B reduced platelet clumping in the lab, which is relevant if you take blood thinners.
• Immunity and the gut. Lion's Mane contains beta glucans, a type of fibre. Mouse studies showed more activity in gut immune tissue, and lab studies with human stool samples showed changes in gut bacteria.
• Antioxidant and anti-inflammatory activity. Extracts neutralised free radicals and lowered inflammatory markers in cells and rodents.

As a food, the fresh mushroom is low in fat and calories and provides protein, some B vitamins and minerals such as potassium, zinc and manganese. In the small amounts found in supplements, those nutrients make little difference.

Doses, forms and timing in the trials

There is no standard dose. Popular guides suggest anything from 1g to 5g a day, but those numbers aren't drawn from any trial that compared doses. Here is what the studies actually used:

• Around 1g a day of erinacine enriched mycelium (Li, 2020)
• 1.8g a day (Docherty, 2023)
• Around 2g a day baked into cookies (Nagano, 2010)
• 3g a day of powder tablets (Mori, 2009)
• About 3.2g a day of fruiting body powder (Saitsu, 2019)
• A single 3g dose of 10:1 extract (Surendran, 2025)

Comparing these with a label is harder than it looks. A 10:1 extract claims that 10g of dried mushroom went into each 1g, so 1g of extract and 1g of powder are not the same thing. Mycelium grown on grain can carry some of that grain into the final product. And the level of hericenones or erinacines varies widely between products, even when the gram figure looks similar.

On timing, the studies give three rough markers. Single dose effects on one task showed up within one to two hours. Mood questionnaires changed over four to eight weeks. Memory test differences in older adults appeared from week eight. No trial tested morning against evening doses, or with food against without.

Lion's Mane comes as fresh or dried mushrooms, powders, capsules, tablets, liquid tinctures made with water or alcohol, mushroom coffees and gummies. Fresh, it has a mild, seafood-like taste often compared with crab. If you are choosing a supplement, look for the part of the mushroom used, the extract ratio, the beta glucan content if listed, and a UK business name and address on the label.

Side effects and who should check with a GP or pharmacist first

Across the trials, side effects were uncommon and mild. Mori 2009 found no changes in blood tests. In Li 2020, four people out of 49 dropped out with stomach discomfort, nausea or a rash. Other reported effects include diarrhoea, headache and skin itching. There are a few published case reports of allergic reactions, including one case of a serious breathing problem.

Speak to a GP or pharmacist before taking Lion's Mane if you:

• are pregnant or breastfeeding, because there is no safety data for either
• take blood thinners such as warfarin, apixaban, clopidogrel or daily aspirin, given the lab findings on platelets
• take medicine for diabetes, because animal studies showed lower blood sugar
• have an operation coming up, for the same bleeding and blood sugar reasons
• have an autoimmune condition or take immune suppressing medicine, since beta glucans act on immune cells
• have a mushroom or mould allergy, or asthma
• are buying for a child, as none of the trials included children

If a product combines Lion's Mane with other ingredients, check those too. Panax Ginseng, for example, has its own list of possible interactions. Suspected side effects from herbal and complementary products can be reported to the MHRA through the Yellow Card scheme.

Lion's Mane in the UK

In the UK, Lion's Mane is sold as a food or food supplement, not a medicine. The rules follow from that.

• There are no authorised health claims for Lion's Mane on the Great Britain nutrition and health claims register. A supplement can describe the ingredient and the research. It can't promise better memory or focus.
• A product that claims to treat, cure or prevent a condition such as dementia or depression would be treated as a medicine by the MHRA and would need a licence.
• The NHS doesn't publish guidance on Lion's Mane. Its general advice is to tell your GP or pharmacist about any supplements you take, especially alongside prescribed medicine.
• Picking it wild is illegal. Hericium erinaceus is rare in Britain and listed on Schedule 8 of the Wildlife and Countryside Act 1981, so picking it without a licence is an offence. Supplements and shop-bought mushrooms come from cultivated crops.
• Lion's Mane contains no psilocybin and isn't a controlled drug. It's legal to buy and sell.

You'll find it in high street health shops, pharmacies, supermarket coffee aisles and a long list of online brands. Fresh Lion's Mane is grown by specialist UK mushroom farms and turns up at some farmers' markets.

Where StarShroooms fits

StarShroooms contains Lion's Mane as a 2:1 extract, alongside Reishi (20:1), Chaga (10:1), Maitake (10:1), Cordyceps powder, Tremella and full spectrum Panax Ginseng, in a blackcurrant gummy. You take two a day.

None of the trials above tested StarShroooms, and none tested a gummy. We're not going to borrow their results. The claims we can make come from the two nutrients in the formula. Two gummies give 100µg of iodine, and iodine contributes to normal cognitive function. They also give 12mg of pantothenic acid (vitamin B5), which contributes to normal mental performance and to the reduction of tiredness and fatigue.

Every study in this article is linked from our research page, along with the trials for the other ingredients. You can read more about each one in our guides to Reishi, Cordyceps, Chaga, Maitake, Tremella and Panax Ginseng, or see the full mushroom gummies range. If you'd like to try StarShroooms before committing, the Trial Pack has 10 gummies, about five days' worth.

FAQs

Does Lion's Mane actually make a difference?

In some small trials, yes, on specific tests. Older adults with mild memory problems scored higher than placebo after 8 to 16 weeks, and healthy young adults were faster on one attention task after a single dose. Most other tests in those trials showed no difference, the largest study had 77 people, and the effect faded once people stopped. There is no large, long trial in healthy adults yet, so any difference you notice may be small or may not happen at all.

How long does Lion's Mane take to work?

It depends which result you mean. A 2023 UK trial saw one faster reaction score an hour after a single dose. Mood questionnaires changed after four to eight weeks in two studies. Memory scores in older adults separated from placebo from week eight in the 2009 Japanese trial. If you try it, give it at least eight weeks at a steady dose before judging, and bear in mind the trials measured group averages, not how any one person felt.

What are the downsides of taking Lion's Mane?

The main ones are stomach upset, nausea, diarrhoea, headache and skin rash, which were uncommon in the trials. A few people have had allergic reactions, including breathing problems. Lab work suggests it may affect platelets and animal work suggests it may lower blood sugar, so anyone on blood thinners or diabetes medicine should check with a pharmacist first. Long term safety beyond about a year hasn't been studied. Cost is a downside too, given how modest the evidence is.

What does Lion's Mane do to your body?

In the lab, its compounds hericenones and erinacines raised levels of nerve growth factor in cells, and in rodents erinacines reached the brain. In people, researchers have measured test scores and questionnaires rather than what happens inside the body. One Italian study found higher blood levels of pro-BDNF, a precursor of a nerve growth protein, after eight weeks. How the mushroom acts in the human body is still largely unknown.

How much Lion's Mane did the studies use?

Daily amounts ranged from about 1g of erinacine enriched mycelium to about 3.2g of fruiting body powder. The 2023 Northumbria trial used 1.8g a day, and the 2009 Japanese trial used twelve 250mg tablets, or 3g a day. Nobody has compared doses head to head, so there is no proven best amount. Extract ratios make labels hard to compare, because 1g of a 10:1 extract is not the same as 1g of plain powder.

Is fruiting body or mycelium Lion's Mane better?

Nobody knows yet, because no trial has compared them. The fruiting body is the shaggy white mushroom you can cook, and it contains hericenones. The mycelium is the root-like network, and it holds most of the erinacines. The Japanese trials used fruiting body powder, while the 49 week Taiwanese trial used mycelium bred for extra erinacine A. When choosing a supplement, check the label says which part was used and how it was extracted.

Is there evidence for Lion's Mane and anxiety or depression?

Two small studies found lower scores on depression and anxiety questionnaires in people taking Lion's Mane, but one had only 30 women and few differences from placebo, and the other had no placebo capsule. Lion's Mane has never been compared with antidepressants, and it can't be sold in the UK as a treatment for any condition. If you're struggling with low mood or anxiety, speak to your GP, and don't stop prescribed medicine without their advice.

Is there any evidence for Lion's Mane and ADHD?

No. We couldn't find any trial of Lion's Mane in adults or children with ADHD. The studies on attention were in healthy adults, took place over one day or 28 days, and found a difference on one task out of many. None of the trials included children at all. If you or your child have ADHD, talk to your GP or specialist before adding any supplement, particularly alongside prescribed medication.

Is Lion's Mane a magic mushroom, and is it legal in the UK?

It isn't a magic mushroom. Lion's Mane contains no psilocybin, has no psychedelic effect and isn't a controlled drug, so buying and selling it is legal. Picking it wild is different. The mushroom is rare in Britain and protected under Schedule 8 of the Wildlife and Countryside Act 1981, so collecting it without a licence is an offence. Everything sold in shops is grown on farms.

Is it safe to take Lion's Mane every day?

The trials gave it daily for up to 49 weeks, and side effects were uncommon and mostly mild, such as stomach discomfort or a rash. That is reassuring but limited, because the groups were small and nobody has followed people for years. Check with a GP or pharmacist first if you're pregnant, breastfeeding, have surgery planned, have an autoimmune condition or take blood thinners or diabetes medicine. Stop if you notice a rash or breathing trouble.

Can I get the same results from a gummy or mushroom coffee?

We don't know, and no brand can honestly say so. The trials used tablets, capsules, cookies and powders at 1g to about 3g a day, and none tested a gummy or coffee. Many drinks and gummies contain much less Lion's Mane than the trials did, or use an extract with a different make-up. If you use them, think of them as a way to include the mushroom in your routine, and read the trials on their own terms.

Sources

• Mori et al., Phytotherapy Research, 2009
• Nagano et al., Biomedical Research, 2010
• Saitsu et al., Biomedical Research, 2019
• Vigna et al., Evidence-Based Complementary and Alternative Medicine, 2019
• Li et al., Frontiers in Aging Neuroscience, 2020
• Docherty et al., Nutrients, 2023
• La Monica et al., Nutrients, 2023
• Surendran et al., Frontiers in Nutrition, 2025
• Menon et al., systematic review, Frontiers in Nutrition, 2025
• Great Britain nutrition and health claims register, GOV.UK
• Wildlife and Countryside Act 1981, Schedule 8