Inonotus obliquus · supplement
Evidence tier: insufficient
Chaga is Inonotus obliquus, a fungus that grows as a hard, black, cracked mass on the trunks of birch trees. It is sold as a powder, a tea, an extract or in capsules.
Preclinical only. Polysaccharides, beta glucans and birch derived triterpenoids such as inotodiol and betulinic acid derivatives show immune modulating and antioxidant activity in cells and animals (MSK). The mechanism that is demonstrated in people is a harmful one: chaga is very high in oxalate, which can deposit as crystals in the kidney.
No human evidence. MSK states that the safety and efficacy of chaga have yet to be evaluated in clinical studies; every claimed benefit (immunity, inflammation, antioxidant, blood sugar, cancer) comes from cell and animal work. NCCIH has no chaga fact sheet. What is documented in people is harm: three published cases of oxalate kidney damage after months of daily use (PMID 23149251, PMID 32419395, PMID 35451393). For consumer purposes there is no benefit that can honestly be stated.
No safe or effective human dose has been established (MSK). The kidney injury cases involved 4 to 5 teaspoons of powder a day for 6 months, and 10 to 15 g a day with 500 mg of vitamin C for 3 months (MSK).
No evidence based schedule exists. Every kidney case followed months of daily use, sometimes with vitamin C, so long uninterrupted use is the pattern to avoid. Stop and see a doctor if urine becomes reduced or foamy, legs or ankles swell, or there is unusual tiredness.
Pregnancy: avoid
Breastfeeding: avoid
Active compounds: oxalic acid (oxalate), very high, triterpenoids including inotodiol, betulin and betulinic acid derivatives, polysaccharides and beta-glucans, phenolic acids, ergosterol, melanin
Remedies using Chaga · Browse by body system · Check it against what you take
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.