Do Mushroom Supplements Work? The Trials, Species by Species

Mushroom supplements have been tested in people far less than their reputation suggests, and the answer differs by species. Lion's mane has one 30-person placebo-controlled trial at 3 g a day, run by a producer's laboratory, in which cognitive scores rose over 16 weeks and fell back within four weeks of stopping; reishi did not change HbA1c, cholesterol or body mass index in a Cochrane review of 398 people with type 2 diabetes or cardiovascular risk factors; cordyceps raised an exercise threshold by 10.5% in 20 older adults and changed nothing in 22 trained cyclists; chaga has never been tested in a human trial and carries a documented kidney hazard.^{1, 4, 7, 10, 11} No mushroom holds an authorised health claim in Great Britain, which is a statement about the register, not proof of no effect.

Sources checked on 29 October 2026.

Do mushroom supplements work?

Where no trial exists, "not tested in people" is not "does nothing". The 2025 systematic review of lion's mane pooled two trials, one randomised and one pilot, to a 1.17-point gain on a 30-point cognitive scale in older adults; the Cochrane reviews of reishi found no effect on blood sugar or cholesterol and no survival data in cancer.^{4, 6, 15}

What is a mushroom complex, and does a blend work better than one species?

A "mushroom complex" blends several species at a fraction of any trial dose. No trial has compared a blend with a single species, and two capsules cannot hold the 3 g a day of lion's mane from the one positive cognition trial and the 5.4 g a day of reishi extract from the fatigue trial.^{1, 5} That is not a verdict on the format; a blend delivers what its label states per serving.

Which mushroom is best for what? The species evidence table

Lion's mane and reishi were tested for different things, never against each other. Brain: lion's mane has most of the placebo-controlled cognition trials, in older adults with impairment rather than healthy people with brain fog, and maitake and snow fungus one each (what lion's mane is good for; does lion's mane help with ADHD). Energy: reishi's fatigue trial and cordyceps's threshold result (what reishi is good for; what cordyceps does for the body). Mood: two lion's mane trials, cookies in 30 menopausal women (two complaint-scale items below placebo) and 41 young adults (a stress trend, p = 0.051); persistent low mood or anxiety is a GP matter.^{2, 17} Sleep: one controlled trial scored it, with no sleep finding reported. Gut, liver, hormones, PCOS (now called PMOS by the NHS), fertility, hair, inflammation, arthritis, longevity, "antioxidant" effects: nothing in the table measured them; testosterone belongs to shilajit's one trial. Healthiest: not a measured quantity, and no trial has ranked species; the shiitake and maitake studies used the whole mushroom (can you eat shiitake every day?; is maitake safe?).^{12, 13} This guide also covers are mushrooms good for you, ashwagandha vs lion's mane, what snow fungus is good for, and two plants sold beside them, what ginkgo biloba is good for and what ginseng is good for.

How long do mushroom supplements take to work, and when should you take them?

In the lion's mane trial that found a difference, scores separated from placebo at week 8 and were still rising at 16; the reishi fatigue trial ran 8 weeks, the cordyceps trial 12, the maitake trial 18 and the one lion's mane study in early dementia 49.^{1, 5, 10, 13, 16} No trial measured blood levels, so there is no figure for how long it stays in your system; in the 16-week trial the gain was gone four weeks after stopping.¹ No trial has compared morning with night.^{1, 2} How lion's mane makes you feel and how you feel after taking reishi gather the reports.

What do clinicians and regulators say about mushroom supplements?

The Great Britain nutrition and health claims register holds no authorised claim for any mushroom.²⁴ Every mushroom row on it (shiitake immune, maitake and king oyster, reishi "stimulates the body in exhaustion", cordyceps antioxidant, immune and endurance, oyster mushroom, yeast beta-glucan) is non-authorised, and lion's mane, chaga and shilajit have no row at all. The Advertising Standards Authority said on 21 November 2024 that "there are no authorised claims for mushrooms themselves", that the word "functional" without an authorised partner claim "is likely to be a problem", and that medicinal claims belong only to MHRA-licensed medicines; it has upheld rulings on 24 July 2024 and in 2025 and 2026 against focus, memory, immunity, anxiety, stress and ADHD wording on mushroom products.²⁴ So the claims on a lawful UK mushroom gummy belong to its vitamins and minerals.

Is any mushroom supplement a novel food in the UK?

A novel food had no significant history of consumption in the UK or EU before 15 May 1997 and needs authorisation before sale.²⁵ The positions below come from European Commission consultations and the Finnish Food Authority, which GB tracks; the FSA's GB list of novel-food consultation outcomes, last updated 26 June 2026 and checked on 29 October 2026, names no mushroom other than enriched button mushrooms, so each is "GB position inferred".²⁸

• Lion's mane: fruiting body and its water extracts not novel (Commission consultation Ares(2025)1618080); dried mycelium powder novel (Ares(2019)6700914). So lion's mane is not illegal in the UK as a mushroom or extract; mycelium products need authorisation, and picking wild hedgehog fungus, Hericium erinaceum, protected under Schedule 8 of the Wildlife and Countryside Act 1981, is the real offence.²⁶
• Reishi: fruiting body not novel; mycelium novel.
• Chaga: novel except broken, or as a water or ethanol extract, in a food supplement; in coffee, cocoa or smoothies it would need authorisation.
• Cordyceps: Ophiocordyceps sinensis and Samsoniella hepiali (the Cs-4 species) not novel; Cordyceps militaris named in the ASA and CAP guidance of 21 November 2024 as likely to be treated by the FSA as an unauthorised novel food.²⁴
• Shiitake and maitake: long-standing foods; not novel.
• Shilajit: not novel only as a food supplement; in honey, coffee or drinks it is novel.

How do you read a mushroom supplement label?

Most human trials used the fruiting body, the mushroom itself; the one lion's mane trial that used mycelium used one standardised to 5 mg/g of erinacine A, not mycelium-on-grain.¹⁶ Whether mycelium came with its grain, because grain starch inflates a "polysaccharide" figure unless beta-glucan is measured by the validated method that subtracts starch.²² The extract ratio against the milligrams: "10:1" means 10 g of mushroom made 1 g of extract, so "1,200 mg whole-mushroom equivalent" at 10:1 is about 120 mg of extract. And a beta-glucan percentage with a batch certificate of analysis, because in one survey only 5 of 19 reishi supplements matched their labels.²³ What mushroom powder is used for goes through powders, extracts, capsules, gummies and coffee by what each delivers per serving, ranking none above another.

What are the risks, and who should not take mushroom supplements?

Chaga and the kidneys. Chaga is extremely high in oxalate: one analysed powder held 14.2 g per 100 g, and three published cases of kidney failure followed daily powder, 3 to 15 g a day, taken for three months to five years, one in a person also taking 500 mg of vitamin C a day.^{7, 8, 9} People with kidney disease or a history of kidney stones should not take chaga without medical advice; can chaga be harmful has the full account, repeated on what chaga is good for, chaga tea every day and does chaga get you high.

Lion's mane and the forum reports. Anxiety, panic, low mood, depersonalisation, anhedonia, emotional blunting and low libido have been reported on online forums by people taking lion's mane, most with a disclosed confounder. The trials, to 10 g a day and 49 weeks, reported no serious adverse effects; the 2025 review lists stomach discomfort, headache and allergic reactions as under-reported possibilities; a PubMed search for case reports pairing lion's mane with those psychiatric terms returned none on 29 October 2026.^{3, 15, 16} Lion's mane side effects has the full account; does lion's mane get you high answers the psychedelic confusion, as is shiitake a psychedelic does for shiitake.

Reishi powder and the liver. Reishi was well tolerated in trials at up to 5.4 g a day of extract, but three published cases of liver injury, one fatal, involved reishi powder, one taken with alcohol.¹⁹ Dark urine, pale stools or yellowing on any supplement mean stop and see a GP.

Shiitake and the skin. Raw or undercooked shiitake can cause shiitake dermatitis, an itchy streaky rash a day or two after eating, lasting about ten days, and thorough cooking avoids it.¹⁸ A true mushroom allergy is a reason to take none of these.

Heavy metals. Raw shilajit is an Ayurvedic preparation, and in a 2008 survey one in five Ayurvedic medicines bought online contained detectable lead, mercury or arsenic; a 1996 report described two people with lead poisoning from a contaminated cordyceps powder; the shilajit trial used a purified extract.^{14, 21, 29}

Medicines. Some trials of fungal beta-glucans changed immune markers in blood tests, which is a laboratory finding, not an authorised claim, so anyone on transplant medicines, biologics, chemotherapy or immunotherapy asks the specialist first; cordyceps is used in China as an add-on to transplant immunosuppressants.^{12, 20} Levodopa, MAO-B inhibitors, antidepressants, ADHD stimulants, anticoagulants and hormone therapies are unstudied with every species. The cross-species interaction table is on the side effects of mushroom supplements. Nothing here is a reason to stop a prescribed medicine.

Everyone. No trial of these species included pregnant or breastfeeding women, and none was a controlled trial in children, so none is recommended for them. No regulator has set an upper intake; "too many" means more than a trial used and, for chaga, any sustained daily powder. The MHRA Yellow Card scheme takes reports on medicines, vaccines and medical devices; a suspected reaction to a food supplement is one to raise with your GP or pharmacist and to report to your local authority's trading standards or environmental health team, which works with the Food Standards Agency.²⁷

What we don't know

No trial has compared one species with another. The positive lion's mane cognition trial has not been repeated independently; the two trials in healthy adults found one faster attention task after a dose and nothing at 10 g a day for four weeks.^{1, 2, 3} Reishi has no placebo-controlled sleep trial and chaga no human trial at all.^{4, 7}

Frequently asked questions

Is it good to take a mushroom complex every day?

The trials, the longest supplier-run, gave single species daily for 4 to 49 weeks without serious harm; a blend gives each at a fraction of those doses, and chaga in any blend carries the kidney caution above.

Do mushroom supplements make you sleepy?

No trial reported drowsiness for any species. Vivid dreams are reported on forums for lion's mane and have not been studied.

Does any mushroom increase testosterone?

No mushroom has been tested for testosterone in people; the one trial used shilajit, a mineral resin, at 500 mg a day for 90 days.¹⁴

Are mushroom supplements worth it?

Where a trial matches your situation, dose and form; a healthy adult taking lion's mane for brain fog sits outside every positive trial.^{1, 2}

Sources

1. Mori K. Yamabushitake and mild cognitive impairment. Placebo-controlled trial, 30 adults aged 50 to 80, 16 weeks; producer's laboratory. Phytother Res, 2009. PubMed 18844328.
2. Docherty S. Lion's mane, cognition, stress and mood in young adults. Placebo-controlled pilot, 41 adults, 28 days; product from a producer, no other role. Nutrients, 2023. PubMed 38004235.
3. Grozier CD. Hericium erinaceus, metabolic flexibility and cognition. Placebo-controlled trial, 24 adults, 10 g a day; funding not stated. Int J Exerc Sci, 2022. PubMed 36582308.
4. Klupp NL. Ganoderma lucidum for cardiovascular risk factors. Cochrane review, 5 trials, 398 adults; authors ran one included trial. Cochrane Database Syst Rev, 2015. PubMed 25686270.
5. Tang W. Ganoderma lucidum polysaccharide extract in neurasthenia. Placebo-controlled trial, 132 patients, 8 weeks; funding not stated. J Med Food, 2005. PubMed 15857210.
6. Jin X. Ganoderma lucidum for cancer treatment. Cochrane review, 5 trials; no financial interest declared. Cochrane Database Syst Rev, 2016. PubMed 27045603.
7. Kikuchi Y. Chaga mushroom-induced oxalate nephropathy. Case report, 1 patient. Clin Nephrol, 2014. PubMed 23149251.
8. Lee S. End stage renal disease after long-term chaga ingestion. Case report, 1 patient, with oxalate analysis; no conflicts. J Korean Med Sci, 2020. PubMed 32419395.
9. Kwon O. Chaga-induced oxalate nephropathy with nephrotic syndrome. Case report, 1 patient; no conflicts. Medicine, 2022. PubMed 35451393.
10. Chen S. Cs-4 and exercise performance in healthy older subjects. Placebo-controlled pilot, 20 adults aged 50 to 75, 12 weeks; US public funding. J Altern Complement Med, 2010. PubMed 20804368.
11. Parcell AC. Cs-4 and endurance exercise performance. Placebo-controlled trial, 22 trained male cyclists, 5 weeks; funding not stated. Int J Sport Nutr Exerc Metab, 2004. PubMed 15118196.
12. Dai X. Daily shiitake and human immunity. Randomised trial, 52 adults aged 21 to 41, 4 weeks; funding not stated. J Am Coll Nutr, 2015. PubMed 25866155.
13. Jogi EM. Maitake and cognition in healthy older Japanese. Placebo-controlled trial, 47 adults aged 60 and over, 18 weeks; lead authors at a maitake producer. J Nutr Sci Vitaminol, 2026. PubMed 42055721.
14. Pandit S. Purified shilajit and testosterone. Placebo-controlled trial, men aged 45 to 55, size not in the abstract, 90 days; supplier-funded. Andrologia, 2016. PubMed 26395129.
15. Menon A. Hericium erinaceus as a supplement: a systematic review. 26 studies, 8 of them trials; no commercial funding. Front Nutr, 2025. PubMed 40959699.
16. Li IC. Erinacine A-enriched mycelia in early Alzheimer's disease. Placebo-controlled pilot, 68 enrolled, 49 weeks; producer-run. Front Aging Neurosci, 2020. PubMed 32581767.
17. Nagano M. Depression and anxiety after 4 weeks of Hericium erinaceus. Placebo-controlled trial, 30 women; funding not stated. Biomed Res, 2010. PubMed 20834180.
18. Boels D. Shiitake dermatitis in France, 2014 to 2019. Case series, 59 cases; public health agencies. Clin Toxicol, 2022. PubMed 35404185.
19. Reishi liver injury, case reports, 1 patient each. Yuen MF J Hepatol, 2004. PubMed 15464254; Wanmuang H. Fatal fulminant hepatitis. J Med Assoc Thai, 2007. PubMed 17621752; Guedikian R. Liver injury with alcohol use. Cureus, 2023. PubMed 37885515.
20. Hong T. Cordyceps sinensis for kidney transplant recipients. Cochrane review, 5 trials, 447 patients; no conflicts. Cochrane Database Syst Rev, 2015. PubMed 26457607.
21. Saper RB. Lead, mercury and arsenic in Ayurvedic medicines sold online. Product survey, 193 products; US public funding. JAMA, 2008. PubMed 18728265.
22. McCleary BV, Draga A. Measurement of beta-glucan in mushrooms and mycelial products. Laboratory method; authors at the assay maker. J AOAC Int, 2016. PubMed 26957216.
23. Wu DT. Quality consistency of Ganoderma lucidum supplements in the United States. Laboratory survey, 19 products; no competing interests. Sci Rep, 2017. PubMed 28798349.
24. Department of Health and Social Care. GB nutrition and health claims (NHC) register, updated 19 May 2026. gov.uk. CAP News, 21 November 2024: advertising rules for functional mushrooms. asa.org.uk.
25. Food Standards Agency. Novel foods authorisation guidance. Published 30 May 2018. food.gov.uk.
26. Wildlife and Countryside Act 1981, Schedule 8, protected plants, listing Hericium erinaceum. legislation.gov.uk.
27. MHRA. Yellow Card: report a suspected side effect. yellowcard.mhra.gov.uk. Food Standards Agency. How to report a food safety or hygiene issue for members of the public. gov.uk.
28. Food Standards Agency. Outcomes on novel food consultations (GB). Updated 26 June 2026. gov.uk.
29. Wu TN. Lead poisoning caused by contaminated Cordyceps. Case reports, 2 patients. Sci Total Environ, 1996. PubMed 8854946.

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