Reishi is a mushroom used in traditional Chinese medicine, sold for immunity and heart health.
Calculator Official intake Study doses Best form Safety Sources
This is not an essential nutrient, so there is no official daily intake. Only study doses are shown.
These are doses tested in research, not personal advice. Some exceed the upper limit because they were short courses or given under medical care.
1.4-3 g a day
A Cochrane review (5 trials, 398 people, mostly with type 2 diabetes) found 1.4 to 3 g a day for 12 to 16 weeks did not lower HbA1c, cholesterol or blood pressure against placebo.
No best form
Why: Trials of reishi powder showed no effect on heart risk factors.
Too woody to eat; used as tea or extract.
Ask your doctor if you take blood thinners or blood pressure medicines.
Long-term safety is not well studied.
Pregnant, breastfeeding, on medication, or managing a health condition? Check with a doctor or pharmacist before starting a supplement.
Values checked: November 12, 2026.