6 Reishi Mushroom Benefits, Side Effects and Who Should Avoid It (Evidence Rated)

Reishi mushroom benefits are everywhere right now. You'll see reishi in teas, capsules and mushroom gummies. It's a glossy, red-brown mushroom with over 2,000 years of use in Chinese and Japanese medicine.

Here's the short answer: reishi may support immune function, ease fatigue and help with stress and mood. Most of that proof comes from small human studies. Two Cochrane reviews found it does not lower blood sugar or work as a cancer treatment.

This guide rates each of the benefits of reishi mushroom by evidence, so you can see:

• Which benefits have human research behind them, and which rest on lab or animal studies
• What reishi probably won't do
• Side effects, liver safety and drug interactions
• Who should avoid reishi, and how to pick a product worth taking

What Is Reishi Mushroom?

Reishi mushroom is a shiny, red-brown, fan-shaped fungus that grows on dead or dying hardwood trees. Its scientific name is Ganoderma lucidum. In China it is called lingzhi, and in Japan, reishi.

It has been part of Chinese and Japanese medicine for over 2,000 years. Healers used it as a tonic for vitality and calm, which earned it the nickname "mushroom of immortality." That name is history, not a health claim.

• Scientific name: Ganoderma lucidum
• Other names: lingzhi (China), reishi (Japan), "mushroom of immortality"
• Taste: woody and bitter, which is why most people take it as an extract, capsule or gummy
• Parts used: the fruiting body (the cap and stem you can see), the mycelium (the root network) and the spores

Thinking of foraging your own? Be careful. Several shelf fungi on hardwood look alike, so read up on reishi look-alikes before you pick one in the wild.

The Compounds Behind Reishi's Benefits

Two groups of compounds get most of the research attention. Triterpenes, mainly ganoderic acids, give reishi its bitter taste. They are studied for calming and anti-inflammatory activity.

Polysaccharides, mostly beta-glucans, are studied for their effects on the immune system. How much of each you get depends on which part of the mushroom is used and how it is extracted.

Reishi Benefits at a Glance

Reishi benefits range from modest human evidence to lab findings only. That's a wide spread, and most articles list every claim as if it were equal.

So here's each one in a single table, rated by the strongest research behind it. Keep in mind that most reishi trials are small and short, so even the top rating means "promising," not "proven."

6 Potential Reishi Mushroom Benefits

Below are the six reishi mushroom benefits with the most research behind them. Each one gives the claim first, then the best human evidence, its size and its limits.

Each benefit ends with a bold Evidence level line. Use it as a quick filter: the closer a claim sits to "human trial," the more weight it can carry.

1. May Support Immune Function

Reishi's beta-glucans may support immune modulation. That means helping the immune system respond in a balanced way, rather than simply "boosting" it. Lab studies show effects on white blood cells, including natural killer cells.

The best human data comes from people with cancer. A 2016 Cochrane review of 5 trials found that reishi taken alongside standard treatment improved some immune markers. The authors rated that evidence as low quality.

• Who was studied: adults with cancer, not healthy people
• What changed: markers of immune activity, such as certain white blood cell counts
• The catch: benefits for healthy people are still unclear

Evidence level: small human studies.

2. May Ease Fatigue

Fatigue is one of the top reasons people try reishi, and one small trial supports it. In a 2012 pilot trial, 48 women with breast cancer on endocrine therapy were split into a reishi group and a control group.

The reishi group took 1,000 mg of reishi spore powder 3 times a day for 4 weeks. They reported less fatigue and a better quality of life, with no serious side effects.

• Dose: 3 g of spore powder a day, split into three doses
• Length: 4 weeks
• The catch: it was one small trial in one specific group, so the results may not apply to everyone

Evidence level: small human trial.

3. May Help With Stress and Mood

The same 2012 trial also tracked mood. Women in the reishi group had lower anxiety and depression scores than the control group.

Memorial Sloan Kettering notes that trials suggest reishi may reduce anxiety. That fits reishi's long use as a calming tonic, and its common label as an adaptogen.

What's an adaptogen? It's a traditional term for herbs said to help the body handle stress. It is not a medical category, and it doesn't mean a product has been proven to work.

If stress is your main goal, HempLucid's stress support range includes gummies that pair reishi with other well-known botanicals like ashwagandha.

Evidence level: small human studies.

4. May Promote Calm and Restful Sleep

Reishi has a long history as an evening tonic for calm. Many people take it before bed for exactly that reason.

Here's the truth, though: the sleep evidence comes mostly from animal studies. There are no strong human sleep trials yet, so treat better sleep as a traditional use rather than a proven benefit.

• Traditional use: a calming tonic, often taken in the evening
• Lab and animal studies: point to calming effects
• Human trials: none strong enough yet to confirm a sleep benefit

That's why HempLucid's Mushroom Sleep Gummies with CBN & Reishi don't rely on reishi alone. Each gummy pairs reishi with lemon balm, valerian root, CBN and CBD.

Evidence level: traditional use and animal studies.

5. Offers Antioxidant Activity

Antioxidants help limit damage from unstable molecules called free radicals. Reishi's triterpenes and polysaccharides both show antioxidant activity in the lab.

In small human studies summarized in the NCBI herbal medicine chapter on reishi, antioxidant capacity in the blood rose after people took reishi. Whether that leads to better health over time is still unknown.

• What was measured: antioxidant capacity in the blood
• What wasn't measured: long-term health outcomes

Evidence level: small human studies.

6. May Ease Urinary Symptoms in Men

This one surprises a lot of people. Small trials suggest reishi may ease lower urinary tract symptoms in men, such as a weak stream or waking at night to urinate, according to MSK and the Merck Manual.

The trials were small and short. New urinary symptoms can also signal problems that need a proper diagnosis.

See a doctor first. If you notice new urinary symptoms, get them checked before you try any supplement.

Evidence level: small human trials.

What Reishi Probably Won't Do

You may not want to read this, but here we go: some of the most popular reishi claims don't hold up in human research. Cochrane reviews, which pool the best available trials, have looked at two of the biggest.

The first is heart health and blood sugar. A 2015 Cochrane review looked at 5 trials. The 3 with usable data, all in people with type 2 diabetes, showed no improvement in blood glucose, blood pressure or cholesterol.

The second is cancer. The 2016 Cochrane review found too little evidence to use reishi as a first-line cancer treatment, and it's unclear whether reishi helps people live longer.

Reishi is not a cancer treatment. If you have cancer, talk to your oncologist before you take reishi or any other supplement. Many of the bold claims you see online come from test-tube and animal studies, not from people.

Reishi Mushroom Side Effects

Most people tolerate reishi well, and reishi mushroom side effects tend to be mild. In the 2015 Cochrane review, side effects were not serious.

Still, "natural" doesn't mean risk-free. Reishi can affect your liver, your blood and the way some medicines work, so it's worth knowing the signs.

Common Side Effects

Reported side effects are mostly minor and involve the mouth, skin or gut. Susan G. Komen lists dizziness, dry mouth, itching, nausea, stomach upset and rash.

If a side effect bothers you or doesn't go away, stop taking reishi and talk to your doctor. Here's the full list reported across reference sources:

• Dry mouth, throat or nose
• Itching or rash
• Upset stomach, nausea, diarrhea or constipation
• Dizziness or headache
• Trouble sleeping
• Nosebleeds

Is Reishi Bad for Your Liver?

For most people, probably not. Small placebo-controlled trials showed no change in liver enzymes. But NIH LiverTox rates reishi a possible rare cause of liver injury (likelihood score D), based on a few case reports.

In those reports, symptoms usually began 1 to 2 months after starting reishi. One fatal case from 2007 involved a switch to powdered reishi.

Stop and call your doctor if you notice dark urine, yellow skin or eyes, or unusual tiredness while taking reishi.

Sources disagree about powder. The Merck Manual says reishi powder taken for more than a month could harm the liver, while Komen rates powder possibly safe for up to 16 weeks. Neither view proves powder is dangerous, but it's one more reason to choose a tested extract.

Drug Interactions

Reishi may change how your body handles certain medicines. Memorial Sloan Kettering lists several interactions worth knowing.

If you take any prescription, check with your doctor or pharmacist first. That goes double for CBD, which can also affect how the liver processes some medications.

One more thing: reishi spore powder may raise a tumor marker called CA72-4. If you take it, tell your doctor before any blood work.

Who Should Avoid Reishi

Reishi isn't a good fit for everyone. Some people have a higher risk of side effects, and others take medicines that reishi may interfere with.

Skip reishi, or get your doctor's okay first, if any of these apply to you:

• You're pregnant or breastfeeding
• You have a bleeding disorder or low platelets
• You have surgery coming up. Komen advises that you stop at least 2 weeks before a scheduled surgery
• You have low blood pressure
• You take blood thinners, blood pressure or diabetes medicines, or immunosuppressants, including after an organ transplant
• You have an autoimmune condition or liver disease
• You're allergic to mushrooms
• It's for a child

Not sure where you fit? Bring the bottle to your next appointment. Your doctor or pharmacist can check the label against your medicines in a few minutes.

How to Take Reishi

How you take reishi matters almost as much as whether you take it. The part of the mushroom, the form and the extraction method all change what ends up in your body.

The good news? You don't need a lab to sort it out. A few label checks cover most of it.

Fruiting Body, Mycelium or Spores?

Reishi products come from three different parts of the fungus, and each has a different makeup.

For most people, the fruiting body is the safest bet, since it's the part with the longest history of use. Look for "fruiting body" on the label.

Common Forms

Reishi comes in five main forms. Tea is the traditional route, but it's bitter enough that many people give up on it.

Gummies and capsules hide that taste, which makes a daily habit easier. If you're deciding between formats, compare powder, capsules or gummies side by side.

• Tea or decoction: traditional, but very bitter
• Powder: easy to stir into drinks; raw powder is less concentrated than extract
• Extract capsules: concentrated and tasteless
• Tinctures: liquid extracts taken by the dropper
• Gummies: easy to take with no bitter taste, and often combined with other ingredients

How Much Reishi to Take

There is no standard reishi dose. Amounts vary a lot by form, so a number that's right for raw powder is wrong for an extract.

• Usual range: 500 mg to 3 g a day, according to LiverTox
• Extract vs dried mushroom: extract is roughly 10 times more concentrated
• Best rule: follow the label on your product

Want more detail on amounts and timing? Our reishi dosage guide covers both.

What to Look for on the Label

Not every reishi product is made the same way. Before you buy, check the label for these five things:

• Ganoderma lucidum named on the label
• "Fruiting body" listed as the part used
• An extract ratio (such as 10:1) or a beta-glucan percentage
• The reishi amount listed on its own, not hidden in a proprietary blend
• A third-party Certificate of Analysis (COA) you can look up

That last one matters more than most people think. The FDA does not approve supplements before sale, so independent testing is how you know what's really in the bottle. HempLucid posts the lab results for every lot.

Reishi in HempLucid Mushroom Gummies

Want reishi without the bitter tea? HempLucid makes two functional gummies built on organic reishi fruiting-body extract. Both pass the label checklist above: the mushroom part, the exact amount and the lab results are all public.

Every lot is tested by a third-party lab, and you can look up its COA on HempLucid's lab results site. The Mushroom Sleep Gummies alone have more than 4,000 five-star reviews.

Mushroom Sleep Gummies

The Mushroom Sleep Gummies are made for winding down at night. Each one combines 750 mg of reishi with lemon balm, valerian root, 15 mg of CBN and 30 mg of CBD, with no melatonin.

The label suggests starting with half a gummy and increasing slowly, up to 3 a day. Taking them at the same time each evening helps you judge how they work for you.

Stress Mushroom Gummies

The Stress Mushroom Gummies are made for a calm, steady mood during the day. Each one pairs 250 mg of reishi with 250 mg of cordyceps, 175 mg of ashwagandha, GABA and 25 mg of CBD.

They also contain 2.5 mg of Delta 9 THC, so they're for adults 21 and over. If you're new to THC, the label suggests half a gummy and a full two-hour wait before taking more.

Want to try both? The Sleep, Stress & Focus bundle adds the lion's mane focus gummy, and HempLucid backs its gummies with a 30-day money-back guarantee.

Good to know: these gummies contain hemp-derived THC (1.5 mg in each Sleep gummy, 2.5 mg in each Stress gummy). THC may show up on a drug test, and you shouldn't drive until you know how a gummy affects you. The amounts and forms of reishi in these gummies also differ from those used in the studies above, such as 3 g a day of spore powder.

Shop all mushroom gummies

Reishi Mushroom FAQs

Still have questions? Here are quick answers to the ones people ask most about reishi.

If your question involves a medicine you take, your pharmacist will have the best answer, since interactions depend on the exact drug and dose.

Is it safe to take reishi every day?

For most healthy adults, daily use appears to be fine. Komen rates reishi extract possibly safe for up to one year, and most reishi mushroom side effects are mild.

Short breaks are a smart habit, and so is a check-in with your doctor if you take medication. Here's how much reishi per day makes sense.

How long does reishi take to work?

Reishi isn't a quick fix. Its effects build gradually, so most people take it daily for several weeks before they notice a change.

For a closer look at the timeline, see how long reishi takes to work.

Does reishi make you sleepy?

Reishi feels calming for some people, which is why many take it in the evening.

It isn't a sedative, though, and it affects everyone differently. Here's the best time to take reishi for your goals.

Does reishi get you high?

No. Reishi is not psychoactive and contains no psilocybin, so it won't change how you perceive things.

The exception is a product that also contains THC. Gummies that combine reishi with THC, like HempLucid's Sleep and Stress gummies, can cause THC effects, so start low.

Can you take reishi with CBD?

Many people do, and HempLucid's gummies combine the two. Research on the pairing itself is limited, though.

Both reishi and CBD may affect the liver enzymes that break down medications. If you take prescriptions, ask your pharmacist before you combine them.

What is the difference between reishi and lion's mane?

Both are functional mushrooms, but people use them for different goals.

• Reishi: traditionally used for calm and immune support, often in the evening
• Lion's mane: used for focus and clear thinking, usually earlier in the day

Want the daytime option? Try HempLucid's Lion's Mane Gummies for Focus.

The Bottom Line

What's the bottom line here? Reishi mushroom benefits look most promising for immune support, fatigue and mood. The human trials are small, though, and larger ones are still needed. Reishi won't lower blood sugar or treat cancer.

If you want to try it, keep it simple:

• Choose a fruiting-body product with the reishi amount on the label
• Check that a third-party COA is available
• Start low and give it a few weeks
• Talk to your doctor first if you take any medication

Ready to add reishi to your routine? Browse HempLucid's mushroom gummies, each with its lab results a click away.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Sources

1. NCBI Bookshelf. Ganoderma lucidum (Lingzhi or Reishi): A Medicinal Mushroom. Herbal Medicine: Biomolecular and Clinical Aspects, chapter 9.
2. Cochrane review, 2016. Ganoderma lucidum (Reishi mushroom) for cancer treatment.
3. Pilot trial, 2012. Spore powder of Ganoderma lucidum and cancer-related fatigue in breast cancer patients on endocrine therapy.
4. Memorial Sloan Kettering Cancer Center. About Herbs: Reishi Mushroom.
5. Merck Manual Consumer Version. Reishi.
6. Cochrane review, 2015. Ganoderma lucidum mushroom for the treatment of cardiovascular risk factors.
7. NIH LiverTox. Lingzhi (Reishi).
8. Case report, 2007. Fatal fulminant hepatitis associated with Lingzhi mushroom powder.
9. Susan G. Komen. Reishi mushroom.
10. U.S. Food and Drug Administration. Dietary Supplements.