Reishi (Ganoderma lucidum)
Reishi is a classic tonic mushroom, traditionally taken for immunity, calm and sleep. The modern evidence is thinner than its reputation suggests.
Not medical advice. For education only. Reishi can interact with medication — read the safety section, and talk to a clinician before use.
What the evidence shows
Small trials show Reishi can shift immune-cell markers in the blood — but a marker change is not the same as a proven clinical benefit. A Cochrane review concluded Reishi should not be used as a first-line cancer treatment, and that evidence for it as an adjunct is weak. Its sleep and stress claims are largely traditional, without robust outcome data.
Evidence level: preliminary (surrogate markers); traditional for calm and sleep.
How it's used
Dual-extract (water and alcohol, to capture both polysaccharides and the bitter triterpenes) powder, capsules, tincture and tea. The triterpene content is a meaningful Reishi-specific quality marker.
Safety
Dizziness, dry mouth, GI upset and rash have been reported, with rare reports of liver injury from powdered forms. Important: Reishi can have antiplatelet effects and may prolong clotting — use caution with anticoagulants and antiplatelets (warfarin, aspirin, clopidogrel). Being immune-active, it may oppose immunosuppressants (caution in transplant or autoimmune conditions), and may add to blood-pressure or blood-sugar medication. Avoid in pregnancy and breastfeeding.
Quality notes
Favour fruiting-body or dual-extract products that publish a measured beta-glucan percentage (and, ideally, triterpene content) with a third-party COA.
Sources
- Jin et al., Cochrane Database of Systematic Reviews 2016 (Reishi for cancer).
- Memorial Sloan Kettering, About Herbs — Reishi mushroom.
Explore the other medicinal mushrooms or our full plant catalogue.