reishi

Reishi (Ganoderma Lucidum) is a dietary supplement.

Ganoderma Lucidum

Not yet rated· sourced from the FDA label

Rated against independent regulatory sources·Last updated June 23, 2026·How we rate

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Key facts

Active ingredient: Ganoderma Lucidum
Type: Supplement

What is Reishi?

From the FDA label:A medicinal mushroom traditionally used for immune support and calm.

What the evidence says

Limited evidence

What Reishi is

Reishi (Ganoderma lucidum, also called lingzhi) is a mushroom long used in traditional Chinese medicine and now sold in the US as a dietary supplement—commonly as capsules, powders, extracts, or teas. As with other dietary supplements, the FDA does not review or approve reishi products for safety or effectiveness before they reach the market.

Commonly used for

Marketed as a general wellness or 'immune support' supplementUsed within traditional Chinese medicine practicesTaken by some people in hopes of helping with stress, sleep, or fatiguePromoted by sellers for heart and metabolic health

What the evidence shows

Neither of the authoritative US government resources reviewed (NCCIH and MedlinePlus) publishes a fact sheet specific to reishi, and well-designed human studies are limited. Speaking more broadly about Chinese herbal products, NCCIH states that many studies have been of poor quality, so no firm conclusions can be drawn about their effectiveness. Marketing claims that reishi treats, prevents, or cures cancer, infections, or any other disease are not supported by these sources, and supplements may not legally be sold with claims to treat disease.

Typical dosage

There is no established or government-recommended dose of reishi, and the amount of active compounds can vary from product to product. Do not exceed the amount on the product label, and speak with your doctor or pharmacist before starting reishi—particularly if you are pregnant or breastfeeding, have a medical condition, or take any medications.

Safety

Reishi is sold as a supplement, not a regulated drug, and does not go through the testing that prescription medicines do—so quality and purity can differ between products. NCCIH cautions that some Chinese herbal products have been found to contain things not listed on the label, including undeclared drugs, heavy metals (such as arsenic, lead, and cadmium), pesticides, or the wrong herbs—and that some incorrect herbs have caused organ damage. Choose products carefully and tell your health care provider about any supplement you take. As NCCIH notes, "natural" does not necessarily mean safe.

Side effects

The authoritative US government sources reviewed do not publish a reishi-specific list of side effects, so its full safety profile in people is not well characterized. As a general precaution, stop use and seek medical advice if you notice any reaction—such as digestive upset, a rash, or other unexpected symptoms—and report problems to your health care provider.

Interactions & cautions

The cited US government sources do not describe reishi-specific drug interactions, so its interaction profile is not well characterized. As a general matter, NCCIH and MedlinePlus warn that supplements and medicines can interact in unexpected ways. To be safe, talk to your doctor or pharmacist before combining reishi with any prescription medication or before any surgery.

Sources

This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Summarized from public health authorities; general reference, not medical advice. Talk to a licensed healthcare professional before starting any supplement.

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Information is sourced from public FDA regulatory data. Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.

What people report to the FDA about Ganoderma Lucidum

The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 46 reports naming Ganoderma Lucidum — the active ingredient in Reishi, and the FDA flagged 78% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:

dizziness5 reports
nausea5 reports
alanine aminotransferase increased4 reports
asthenia4 reports
blood calcium increased4 reports
blood magnesium increased4 reports
blood phosphorus increased4 reports
malignant neoplasm progression4 reports

Read these as a signal, not a rate. A report does not mean Ganoderma Lucidum caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label.

Source: openFDA drug/event (FAERS), retrieved September 25, 2026.

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Key facts

What is Reishi?

What the evidence says

What Reishi is

Commonly used for

What the evidence shows

Typical dosage

Safety

Side effects

Interactions & cautions

Sources

Ways to save

What people report to the FDA about Ganoderma Lucidum

Reviews

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