What Is Reishi Mushroom? Benefits, Side Effects and Safety

Reishi (Ganoderma lucidum, also called lingzhi) is a glossy, woody mushroom that has been used in traditional medicine across Asia for hundreds of years and is now sold as capsules, powders, extracts, teas and gummies. Human research on it is mixed: some small studies point to possible effects, others found none, and no standard dose has been set. It also carries real cautions around the liver, bleeding and medications, so read the safety sections below before you buy anything.

Disclosure: this site and Pilly Labs are under common ownership.

What is reishi mushroom?

Reishi is a fungus that grows on hardwood trees in warm, humid places. Healthline describes it as native to hot, humid parts of Asia. A mushroom grower’s guide adds that it also occurs in Europe and North America. The fruiting body is a shelf-like or kidney-shaped cap with a lacquered red or rust-colored top and a pale, porous underside. Other names are lingzhi, ling zhi and “mushroom of immortality.”

You will rarely eat it as food. WebMD says it can be tough and bitter, so people usually take it dried or as an extract in liquid, capsule or powder form. Memorial Sloan Kettering adds tablets and teas to that list and says its main active compounds are beta-glucan polysaccharides and triterpenes.

For the long history and how it compares with modern studies, see our guide to reishi’s traditional use versus clinical evidence.

What does reishi do to the body?

The honest answer is that it is studied for several things and proven for none of them in everyday use. Memorial Sloan Kettering says reishi is used in many Asian countries to increase energy, support the immune system and for general health. The table shows what its clinical summary and Healthline report.

Most of the strongest-sounding findings come from test-tube or animal work. WebMD says the evidence consists of lab research and some small human studies.

Is reishi a hallucinogen or psychedelic?

No. Reishi is a woody shelf fungus used as a general-wellness supplement, not a psychedelic. The side effects that Memorial Sloan Kettering lists are nausea, insomnia, dry mouth, constipation, itching and vertigo. Hallucinations are not among them. If you want to be sure about a particular product, read the whole ingredient list and ask the seller for the full label. A label that names only reishi or other functional mushroom extracts is the thing to look for.

What does reishi do to the brain, and does it help sleep?

Memorial Sloan Kettering says clinical studies indicate possible anxiety-lowering effects. A pilot study of reishi spore powder in Alzheimer’s disease did not find it helpful. Healthline says reductions in anxiety and depression have been reported in people with cancer, but it is unclear whether healthy people would see the same.

Sleep is mixed. A mushroom grower’s guide says some studies suggest reishi supports sleep quality, yet Memorial Sloan Kettering lists insomnia as a possible side effect. Human evidence is indication-specific, and broad retail outcomes are not established. Our page on reishi for sleep goes through the studies. If you are using a calming product with other botanicals, note that NCCIH’s valerian summary and its passionflower summary describe limited or inconsistent evidence and give safety cautions.

Is it okay to take reishi every day, and how long does it take to work?

No agreed daily amount exists. WebMD says optimal doses have not been set for any condition and that quality and active ingredients vary widely between supplements. Healthline cites a 2015 review with no agreed dosage and recommended amounts of 1.5 to 9 g per day, and notes that an extract is roughly ten times more concentrated than the whole mushroom. Many finished products contain far less than that, so research at higher doses cannot tell you what a particular gummy or drop does.

Studies lasted weeks, not hours. Healthline mentions 4-week and 4-to-12-week studies. No timeline is guaranteed, and individual experiences vary. If you take medication or have a liver, bleeding or immune condition, ask a clinician before making reishi a daily habit.

What are the side effects and downsides of reishi?

WebMD also notes that the FDA regulates supplements differently from drugs: makers do not have to show a product is safe or effective before selling it.

Is reishi bad for your liver, or good for it?

Both questions have a short answer. Memorial Sloan Kettering lists liver injury as a possible side effect and describes case reports of liver toxicity with powdered reishi, one leading to death. It also describes a man who had been taking reishi for liver function whose liver enzymes and nodules resolved after he stopped. Healthline says a 2004 study found no harm to liver or kidneys in healthy adults taking an extract for 4 weeks. It adds that, because other factors were involved in the reports, it is hard to say whether the mushroom itself caused the damage.

On benefits, Memorial Sloan Kettering says extracts showed liver-protective properties in lab and animal studies. That is not the same as showing a benefit in people. If you have liver or kidney problems, Healthline lists you among the groups who should probably avoid reishi, and a clinician should make the call.

What should you not mix with reishi?

Talk to a clinician or pharmacist before combining reishi with any of these:

• Blood thinners and antiplatelet drugs (warfarin, heparin, aspirin, NSAIDs): WebMD and Memorial Sloan Kettering both say reishi may raise bleeding risk, and MSK notes reishi extracts may prolong clotting tests.
• Blood pressure and diabetes medicines: WebMD says reishi may interact with blood pressure drugs and that risk may be higher with diabetes medications.
• Immunosuppressants: Memorial Sloan Kettering says reishi may not be safe with them.
• Other supplements affecting clotting or blood pressure: WebMD names ginkgo and fish oil.
• Sedatives and alcohol: Pilly Labs’ own safety notice says reishi and other calming ingredients may add to sedative effects. Products that also contain valerian or passionflower call for extra care.
• Cancer care: Memorial Sloan Kettering says reishi spore powder may raise the tumor marker CA72-4 and interfere with test results. Tell your care team about every supplement you take.

Our mushroom supplement interaction guide covers more. If you have an adverse reaction, Pilly Labs’ notice points to the FDA reporting line, 1-800-FDA-1088.

Does reishi get rid of belly fat?

Reishi is not a belly-fat or weight-loss product. Memorial Sloan Kettering’s summary reports that in people with fibromyalgia, reishi did not change blood or body measurements. The things reishi is studied for sit elsewhere in the table above. For belly fat, a clinician or dietitian is the right source.

Is reishi different for women?

The research does not split results by sex in a way that tells women to expect something different. The practical points are the cautions: WebMD and Healthline both advise people who are pregnant or nursing to avoid it, and Memorial Sloan Kettering flags possible effects on autoimmune skin disease. Pilly Labs’ notice says the same for people with autoimmune conditions. Check with your clinician if any of those apply.

Which is better: reishi or lion’s mane? And which mushroom is healthiest, best for energy or best for the gut?

Neither is better in general; they are studied for different things. Reishi is mostly discussed for relaxation, immune and general wellness. Lion’s mane is mostly discussed for focus, but the human research is small. A 2025 acute study of 3 g of lion’s mane extract in 18 adults found no significant overall effect on cognition or mood, with one isolated task signal. Our comparison of lion’s mane, cordyceps and reishi goes into each.

• Healthiest: food mushrooms have the better-studied record. Harvard Health reports an observational study of over 36,000 men in which eating mushrooms once or twice a week was linked to an 8% lower prostate cancer risk and three or more times a week to 17% lower. It cannot prove cause and effect. Harvard says shiitake, oyster, maitake and king oyster have the most ergothioneine; reishi is not on that list. A Cleveland Clinic dietitian says eating whole mushrooms is a better bet than processed mushroom products.
• Energy: cordyceps is the mushroom people usually search for here. Some exercise outcomes have been studied, with findings that vary by product, population and outcome. It is not a guaranteed energy source.
• Gut: a mushroom grower’s reishi guide says research suggests reishi may benefit the gut microbiome, and it describes the findings as preliminary. Cleveland Clinic says mushrooms can cause digestive issues, so speak to a clinician or dietitian first if you have digestive problems.

How do you read a reishi supplement label?

Check these before you compare products:

• Does the label say fruiting body, mycelium or spore powder? They are different materials.
• Is the reishi amount listed on its own, or is it inside a combined blend?
• Is the amount an extract (for example 10:1) or whole powder? Healthline says extracts are about ten times more concentrated.
• What else is in it: other botanicals, sugar or sweeteners?

To see how this works on real labels, the examples below come from Pilly Labs, whose products include reishi. If you want an example of a reishi gummy with added botanicals, compare the Reishi Relax Gummies label. The product page names valerian and passionflower in its safety text and warns they may cause drowsiness. It also says exact serving size and ingredient amounts are being reverified, so read the bottle you receive.

For criteria-based matching: if you want a reishi-led liquid, Reishi Calm Drops is the closest match on its label. If you need every species amount disclosed separately, the two blends above do not provide that. This is a match by label facts, not a promise of any result. Research on reishi as an ingredient does not prove what a finished product does. For more on gummies in general, see do mushroom gummies work.

Before you order

• Ask the seller for the current label showing the reishi amount per serving and whether it is fruiting body, mycelium or spore powder.
• If a product uses a blend, ask whether the reishi amount inside it can be disclosed.
• If you take blood thinners, blood pressure or diabetes medicines, immunosuppressants or sedatives, or you are pregnant, nursing, have liver problems or an autoimmune condition, ask a clinician first.
• If you have a mushroom or mold allergy, check with a clinician before using any mushroom supplement.
• If a refund matters to you, Pilly Labs’ policy gives 30 days from delivery to contact info@pillylabs.com, with one refund per product per customer.

By TopShelfMushrooms.com Editorial Team

This article is for general information purposes only and does not constitute medical advice. Consult your doctor or qualified healthcare provider before making changes to your health routine.