Reishi

Also known as ganoderma lucidum, reishi mushroom.

Last reviewed October 9, 2026 · Jump to references

What is Reishi?

In plain words

Reishi is a mushroom used in traditional medicine and sold in powders and extracts. Its substances interact with the gut and may affect signals in the body's defense system. Researchers study it for effects on immune function, inflammation, and fatigue, but human studies have not clearly established these benefits. It can cause side effects and may interact with medicines, including blood thinners.

Technical definition

Reishi is a botanical preparation derived from Ganoderma mushrooms, commonly labeled Ganoderma lucidum, containing polysaccharides such as beta-glucans and lanostane-type triterpenoids. Its constituents have multiple proposed actions rather than one established molecular target; beta-glucans can interact with innate immune receptors such as Dectin-1, while triterpenoids are investigated for effects on inflammatory signaling. In the United States, reishi is marketed as a dietary supplement, not an FDA-approved treatment for disease.

Educational information only. This page does not provide medical advice or determine whether a supplement is appropriate for you. Review supplements with a qualified healthcare professional, especially if you take medication, are pregnant, have surgery scheduled, or have a chronic medical condition.

Evidence by use

Each use is rated on its own. There is no single overall effectiveness score.