Chaga
Best evidence: Animal and cell studies only
Inonotus obliquus
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: effects seen in mice or in a dish. this is the stage at which most supplement marketing quietly starts, and the majority of compounds that look good here do nothing in people.
What is actually being talked about
Betulinic acid and related triterpenes drawn from the birch itself, plus melanin and polysaccharides.
Claim by claim
Antioxidant activity
Animal and cell studies only
Very high antioxidant capacity in laboratory assays. High antioxidant readings in a test tube have repeatedly failed to translate into human health outcomes across many foods, and this is no exception.
Immune and anti-inflammatory effects
Animal and cell studies only
Rodent and cell work only. Human trials are essentially absent.
The honest summary
The weakest human evidence of the group, combined with the clearest documented harm, which is an unusual and unflattering combination.
Who should be careful
Avoid entirely with any history of kidney stones or kidney disease. It also affects blood sugar and may increase bleeding risk.
What is actually in the jar
Two problems worth knowing before buying at all. Chaga is very high in oxalates, and there are published cases of kidney damage in people taking it heavily over long periods. And it is being harvested faster than it forms: a conk takes years to grow and taking it can kill the birch.
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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
Cordyceps
Cordyceps militaris, Ophiocordyceps sinensis
Human trials, weak or mixed
Shiitake
Lentinula edodes
Approved as a drug
Maitake
Grifola frondosa
Human trials, weak or mixed
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.