Maitake
Best evidence: Human trials, weak or mixed
Grifola frondosa
Nothing here is medical advice and nothing here treats or prevents any disease. The grade on each claim describes the strength of the published evidence, not how well the mushroom works. The strongest grade on this page means: trials exist and disagree, or are too small and too poorly designed to conclude anything from.
What is actually being talked about
Beta-glucans, particularly the fraction marketed as D-fraction.
Claim by claim
Immune markers
Human trials, weak or mixed
A small trial in breast cancer patients found measurable immune changes, in both directions depending on dose, with no clinical outcome demonstrated.
Blood sugar
Animal and cell studies only
Consistent effects in rodents. Human data is minimal.
The honest summary
Like shiitake, this is best treated as excellent food rather than as medicine. The evidence for the supplement is thin; the argument for roasting it is overwhelming.
Who should be careful
May lower blood sugar, which is worth knowing alongside diabetes medication.
What is actually in the jar
Buy it to eat. It is cultivated widely, sold fresh in many supermarkets, and among the best mushrooms there is in a hot oven.
You can also just eat it. Which is a better argument than any capsule on this page. The hen of the woods, maitake sheet
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The others, graded the same way
Lion's mane
Hericium erinaceus
Human trials, promising
Turkey tail
Trametes versicolor
Approved as a drug
Reishi
Ganoderma lucidum
Human trials, weak or mixed
Chaga
Inonotus obliquus
Animal and cell studies only
Cordyceps
Cordyceps militaris, Ophiocordyceps sinensis
Human trials, weak or mixed
Shiitake
Lentinula edodes
Approved as a drug
Several of these interact with real medication. Reishi and cordyceps affect bleeding and blood sugar, chaga is high enough in oxalates to have caused kidney damage in heavy users, and anyone in cancer treatment should raise turkey tail with their oncology team rather than adding it independently. Tell your doctor what you are taking.