Reishi Mushroom

Supplements · Adaptogens & Stress Herbs · Supplement, Typed Supps

A mushroom used traditionally for calm, now studied for immune effects.

Stage by stage

Intake (Extract capsule): Contains beta-glucans and other active compounds.
Small intestine (Absorbed): Active compounds absorbed in the small intestine.
Bloodstream (Interacts with immune cells): Circulates and interacts with immune cell activity.
Stress response (Mild calming effect): Also studied for mild calming effects on the stress response.

What the evidence supports

Modulating immune-cell activity — limited evidence. Small human trials and a Cochrane review of cancer patients suggest reishi can partly restore immune measures depressed by chemo- or radiotherapy, but the trials were few and of low to very low quality.
Shrinking tumours or improving cancer survival on its own — insufficient evidence. The Cochrane review found no good evidence it works as a standalone cancer treatment; any role is adjunctive at best.
Evidence on Long-term safety of concentrated extracts — insufficient evidence. Trials were short. Isolated reports of liver injury exist with powdered reishi, so extended high-dose use is genuinely under-studied.

Typical dose

1.4–5.4 g daily of extract, usually in divided doses

Upper limit: No established UL; long-term high-dose safety is not well characterised

Timing

Often taken in the evening given its calming reputation.

Time to effect

Weeks: Consistent use for any reported effect in studies.

Medication interactions

Anticoagulants and antiplatelets (e.g. warfarin, aspirin, clopidogrel): Reishi may slow blood clotting, adding to the bleeding risk. (moderate)

Common myth

“Reishi noticeably boosts immunity right away.” In reality: Its immune-modulating research is mostly preliminary and doesn’t show an immediate boost — effects build gradually.