Chaga (Inonotus obliquus) is a fungus that grows on birch and other trees. It has been used in folk medicine for cancer, gastritis and ulcers, and some people take it as a powder for its reported anti-inflammatory and antioxidant effects.
Also known as: chaga mushroom, Inonotus obliquus, birch fungus.
We found no trials in people, so there are no studied amounts. The kidney cases below involved 4 to 5 teaspoons of powder a day for 6 months, and 10 to 15 g a day for 3 months.
It is sold in the US as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling.
What is known in people: we found no clinical trials of chaga. The published human reports are of harm. A 72-year-old woman who took chaga powder for 6 months for liver cancer developed kidney failure needing dialysis; a biopsy showed oxalate crystals, and the authors note chaga contains extremely high levels of oxalate (Kikuchi 2014). A 69-year-old man who took 10 to 15 g a day of chaga powder plus vitamin C for 3 months developed acute kidney injury from oxalate crystals; he needed dialysis and steroids and recovered (Kwon 2022).
The evidence is two case reports, so how common this is cannot be known.
We could not find a single published half-life or time to peak for chaga that applies to a supplement dose, so we do not list one. Plant and mushroom products are mixtures of many compounds, so no single figure would describe them. It has not been studied in people.
How Dose Track handles peptides · Reconstitution calculator · Half-life calculator