What the evidence says. Graded preliminary: chaga has rich antioxidant chemistry and promising mouse, rat and cell data, but there are essentially no controlled human efficacy trials. The only human evidence is ex-vivo lymphocyte assays, while real-world reports document serious kidney harm from its high oxalate content. (Preliminary evidence: Early or small human trials; promising but not yet conclusive.)
What is Chaga?
Chaga (Inonotus obliquus) is a gut and immune supplement used for antioxidant support. NutriDex grades the human evidence as Preliminary. Chaga is a parasitic fungus that grows on birch trees and is sold as a powder, tea or extract for immunity, anti-aging and blood sugar. Its appeal rests on genuinely high levels of antioxidants, beta-glucans and triterpenoids. However, the evidence base is almost entirely preclinical: anti-diabetic, anti-inflammatory and anti-fatigue effects have been shown only in mice, rats and cell cultures. The strongest human-derived data come from ex-vivo experiments where chaga extract reduced hydrogen-peroxide-induced DNA damage in donated lymphocytes (about 35–55%), which does not establish any clinical benefit. No randomized controlled trials in people support the marketed claims. Meanwhile, chaga is extremely high in oxalate (up to ~14 g per 100 g), and multiple case reports link long-term or high-dose use to acute oxalate nephropathy and even end-stage kidney disease. Benefit in humans is unproven; the documented risk is concrete.
Purported Benefits
✓Antioxidant support
✓Immune modulation
✓Anti-inflammatory (claimed)
✓Blood-sugar support (claimed)
Evidence by outcome
The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.
Chaga is very high in oxalate (up to ~14 g per 100 g), and case reports tie prolonged or high-dose use to acute oxalate nephropathy and end-stage kidney disease, especially when combined with vitamin C or in those with kidney disease, diabetes or dehydration. It may lower blood sugar and could add to antidiabetic drugs, and its claimed antiplatelet/blood-thinning activity raises a theoretical bleeding risk with anticoagulants such as warfarin. Avoid in pregnancy, breastfeeding, kidney stones or chronic kidney disease, and before surgery; quality and oxalate content of wild-harvested products are unregulated. Educational only — always check with your doctor or pharmacist before combining Chaga with any medicine.
Chaga drug interactions
Known or theoretical interactions between Chaga and common medications — educational, not exhaustive. Always check with your doctor or pharmacist before combining Chaga with any medicine.
Chaga is most often taken for Antioxidant support, Immune modulation, Anti-inflammatory (claimed), Blood-sugar support (claimed). Antioxidant birch fungus with bold claims but no human efficacy trials.
Does Chaga work — what does the evidence say?
Preliminary evidence. Early or small human trials; promising but not yet conclusive. Chaga is a parasitic fungus that grows on birch trees and is sold as a powder, tea or extract for immunity, anti-aging and blood sugar. Its appeal rests on genuinely high levels of antioxidants, beta-glucans and triterpenoids. However, the evidence base is almost entirely preclinical: anti-diabetic, anti-inflammatory and anti-fatigue effects have been shown only in mice, rats and cell cultures. The strongest human-derived data come from ex-vivo experiments where chaga extract reduced hydrogen-peroxide-induced DNA damage in donated lymphocytes (about 35–55%), which does not establish any clinical benefit. No randomized controlled trials in people support the marketed claims. Meanwhile, chaga is extremely high in oxalate (up to ~14 g per 100 g), and multiple case reports link long-term or high-dose use to acute oxalate nephropathy and even end-stage kidney disease. Benefit in humans is unproven; the documented risk is concrete.
What is the typical dose of Chaga?
No established human dose; products supply ~1–3 g/day of dried sclerotium or extract, but safe long-term dosing is undefined.
Is Chaga safe? Any cautions or side effects?
Chaga is very high in oxalate (up to ~14 g per 100 g), and case reports tie prolonged or high-dose use to acute oxalate nephropathy and end-stage kidney disease, especially when combined with vitamin C or in those with kidney disease, diabetes or dehydration. It may lower blood sugar and could add to antidiabetic drugs, and its claimed antiplatelet/blood-thinning activity raises a theoretical bleeding risk with anticoagulants such as warfarin. Avoid in pregnancy, breastfeeding, kidney stones or chronic kidney disease, and before surgery; quality and oxalate content of wild-harvested products are unregulated.
How many studies support Chaga?
NutriDex cites 7 sources for Chaga, graded "Preliminary".
Does Chaga interact with any medications?
Yes — known or theoretical interactions include: Blood thinners (warfarin, DOACs) (caution), Antiplatelet drugs (aspirin, clopidogrel) (caution). This is educational and not exhaustive; always check with your doctor or pharmacist before combining Chaga with any medicine.
Cite this page
APA
Peh, D. (2026). Chaga (Inonotus obliquus): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 16 Sept 2026, from https://nutridex.info/s/chaga
BibTeX
@misc{nutridex_chaga,
author = {Peh, Daryl},
title = {Chaga (Inonotus obliquus): Benefits, Dosage, Side Effects \& Evidence},
year = {2026},
howpublished = {NutriDex --- The Supplement Research Compendium},
url = {https://nutridex.info/s/chaga},
note = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-09-16}
}
For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.