Reishi: Uses, Benefits, Dosage & Safety

Last updated: June 2026 · Reviewed by the FactoWiki Editorial Team for clarity and source accuracy

What is Reishi?

Reishi (Ganoderma lucidum), known as lingzhi in China, is a woody, bitter mushroom used in East Asian medicine for over two thousand years as a tonic for immunity, energy and long life. Modern supplements use extracts of the mushroom or its spores, standardized for compounds called polysaccharides (beta-glucans) and triterpenes. It is one of the most famous 'medicinal mushrooms,' but its reputation rests more on tradition and laboratory findings than on strong human trials.

What Reishi is commonly used for

In supplements, Reishi is taken for immune support, energy and general wellbeing, and is sometimes used alongside conventional cancer treatment as supportive care — not as a treatment in its own right. It is sold as a wellness tonic; the honest summary is that tradition and lab data are strong while the human evidence is weak.

How Reishi works

Reishi's polysaccharides and triterpenes have shown immune-modulating and anti-inflammatory activity in laboratory and animal studies — for example, influencing the activity of natural killer cells and other immune players. Translating that into measurable benefits in healthy people has proven difficult, and reviews repeatedly highlight small, low-quality trials with inconsistent results.

What the evidence says

Here's an honest snapshot of what published research suggests about Reishi — including where the evidence is limited.

• A GRADE-assessed systematic review and meta-analysis of 17 randomised trials (971 participants) found reishi had modest effects on a few health indices, but rated the overall certainty of evidence as very low. (PubMed)
• A meta-analysis of animal studies on reishi and blood lipids reported contradictory results, underlining how unsettled even the preclinical picture is. (PubMed)
• General background on reishi is summarised by reputable health references; a Cochrane review concluded it should not be used as a first-line cancer treatment, with only weak evidence it might enhance immune response alongside conventional therapy. (MedlinePlus)

Typical dosage used in studies

Research has used a very wide range — from a few hundred milligrams up to several grams of extract per day — over weeks to months, which makes the studies hard to compare. This is general information from research, not a recommendation.

Side effects and safety

Reishi is generally well tolerated short-term, with possible digestive upset, dry mouth and dizziness. There are rare reports of liver problems linked to certain reishi products, so caution is warranted with long-term or high-dose use.

Medication interactions and who should avoid Reishi

Sources & further reading

The evidence summary above is drawn from these sources. For general, authoritative background you can also consult:

• PubMed-indexed study (PMID 40510787)
• PubMed-indexed study (PMID 38116485)
• MedlinePlus
• NIH Office of Dietary Supplements
• NIH National Center for Complementary and Integrative Health

Frequently asked questions

Does reishi boost immunity?

Laboratory and animal studies show immune-modulating activity, but human trials are small and low-quality. A clear immune benefit in healthy people has not been established, despite the confident marketing.

Can reishi treat cancer?

No. A Cochrane review concluded reishi should not be used as a first-line cancer treatment. At most it has been studied as supportive care alongside conventional therapy, not as a cure.

Is reishi good for sleep or stress?

It is traditionally used as a calming tonic, but solid human evidence for sleep or stress benefits is limited.

How much reishi should I take?

Studies use a very wide range with no agreed dose, which is part of why the evidence is hard to interpret. This is general information rather than a recommendation.

Is reishi safe?

It is usually well tolerated short-term, but rare liver problems have been reported. Caution is warranted with blood thinners, with diabetes or blood-pressure medicines, and before surgery.