Reishi mushroom supplement: what it may do and who should avoid it
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- Organic reishi fruiting body capsules. Best for: Adults who want reishi alone in a measured dose. See options on Amazon
- Reishi and shiitake capsules. Best for: Buyers who want a simple two-mushroom formula. See options on Amazon
- Reishi mushroom powder. Best for: People who prefer reishi in tea or coffee. See options on Amazon
What reishi is
LiverTox describes lingzhi, known as reishi in Japan, as a large, reddish-brown mushroom with a fan-like shape that grows at the base of trees. It is rare in the wild, so it is cultivated on logs, sawdust or wood chips. It has a bitter taste and is used in cooking and tea, but mainly in traditional Chinese medicine to improve health and vitality.
Its compounds include polysaccharides, triterpenoids, nucleosides and ergosterols, but LiverTox says the active component responsible for its effects is unknown. Supplements come as capsules, tablets, extracts, powders and teas, and reishi often appears in multi-ingredient products.
What the research shows
| Use | What the evidence says |
|---|---|
| Urinary symptoms in men | Some clinical benefit (MSK) |
| Blood sugar and cholesterol | Mild effects in some studies; no benefit on heart risk factors in type 2 diabetes trials |
| Anxiety | Small clinical studies |
| Cancer | Small studies only; safety and benefit as an add-on not established |
| Overall | No benefit shown in adequate, controlled trials (LiverTox) |
What MSK reports. Clinical studies suggest benefits for lower urinary tract symptoms in men, mild antidiabetic and cholesterol effects, and lower anxiety. However, randomized trials did not support reishi for cardiovascular risk in type 2 diabetes, it did not change measurements in fibromyalgia, and a pilot study of reishi spore powder found no help in Alzheimer's disease.
Cancer. Small studies reported immune and tumor responses in cancer patients and improvements in nausea, fatigue and appetite, but MSK says more research is needed to judge safety and effectiveness as an add-on treatment. Reishi spore powder raised the tumor marker CA72-4 in people treated for digestive cancers, which could confuse test results.
Overall. LiverTox says lab and animal studies suggest many effects, but none has been demonstrated in adequately sized and properly controlled human trials.
Safety and interactions
- Blood thinners. Reishi can increase bleeding risk with anticoagulant or antiplatelet drugs and may prolong clotting tests (INR, PT, APTT).
- Immune-suppressing drugs. Reishi can boost immune response, so it may not be safe if you take immunosuppressants.
- Autoimmune conditions. MSK says its immune effects may trigger or worsen autoimmune skin disease, though cause has not been proven.
- Chemotherapy. Talk with your oncologist; reishi may interact with some cancer treatments.
- Liver. LiverTox reports rare cases of liver injury, usually 1 to 2 months after starting, with symptoms such as fatigue, nausea, abdominal pain, dark urine and jaundice. MSK notes one case with powdered reishi that led to death.
- Other side effects. Nausea, insomnia, dry mouth, constipation, itching and dizziness have been reported.
Capsules, powder or tea?
- Capsules. Easy to measure. LiverTox says usual doses range from 500 mg to 3 grams daily.
- Example label. NOW Foods' Reishi Mushrooms combines 90 mg of 10:1 reishi extract and 300 mg of reishi powder with 150 mg of shiitake extract per 2 capsules, taken twice daily with food.
- Powder and tea. LiverTox notes reishi has a bitter taste and is used to make herbal tea.
- Spore powder. A separate product; MSK notes it raised a tumor marker, so tell your doctor if you use it.
- Mushroom blends. Many products mix reishi with lion's mane, cordyceps or chaga. Check each amount.
How to choose reishi
- Species and part. Look for Ganoderma lucidum and whether the product uses fruiting body, mycelium or spores.
- Amount per serving. Compare mg of reishi, not total blend weight.
- Single mushroom. Choose reishi alone if you want to know what you are taking.
- Organic and tested. Prefer organic products with third-party testing.
- Medical check first. Especially with blood thinners, immune drugs, cancer treatment or liver disease.
What to look for when you buy
Organic reishi fruiting body capsules
Best for: Adults who want reishi alone in a measured dose
Single-mushroom capsules make the reishi amount clear; LiverTox lists usual doses of 500 mg to 3 grams daily.
Watch out: Raises bleeding risk with blood thinners and may not be safe with immunosuppressants. Stop for signs of liver trouble.
See options on AmazonReishi and shiitake capsules
Best for: Buyers who want a simple two-mushroom formula
NOW Foods combines reishi extract and powder with shiitake extract, taken twice daily with food.
Watch out: Same interaction cautions; check you are not doubling up with other mushroom blends.
See options on AmazonReishi mushroom powder
Best for: People who prefer reishi in tea or coffee
Powder can be stirred into tea, one of the traditional ways reishi is used.
Watch out: Measure servings. One fatal liver injury case involved powdered reishi; talk with your doctor first.
See options on AmazonQuestions people ask
- What is reishi mushroom good for?
- Small studies suggest possible help for urinary symptoms in men, cholesterol and anxiety, but LiverTox says no benefit has been proven in adequate trials.
- Is reishi safe?
- Usually well tolerated in short trials, but it can raise bleeding risk, interact with immune drugs, and rarely cause liver injury.
- Can I take reishi with blood thinners?
- Only with your doctor's okay. Reishi can increase bleeding risk and affect clotting tests.
- How much reishi should I take?
- Follow the label. LiverTox lists usual doses of 500 mg to 3 grams daily.
- Is reishi the same as lingzhi?
- Yes. It is called lingzhi in China and reishi in Japan.
Sources
- Reishi Mushroom: About Herbs (mskcc.org), Memorial Sloan Kettering Cancer Center
- Lingzhi, Reishi - LiverTox (ncbi.nlm.nih.gov), National Institute of Diabetes and Digestive and Kidney Diseases
- Reishi Mushrooms 270 mg Veg Capsules (www.nowfoods.com/products/supplements/rei-shi-mushrooms-270-mg-veg-capsules), NOW Foods