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No active regulatory warnings
Sources: FDA MedWatch, EMA EudraVigilance, WHO VigiBase, WADA Prohibited List · 2026-05-29
Updated: 2026-05-29 · v2.0 · Prof. G. Pkhakadze, MD, MPH, PhD📎 Cite 📄 PDF
1 Identity

Chaga

Inonotus obliquus
Conditionally SafeEvidence: LimitedMushrooms
Chaga (Inonotus obliquus) is a parasitic fungus that grows on birch trees in cold climates (Russia, Scandinavia, Canada). The dark exterior (sclerotium) is one of the richest natural sources of melanin and contains betulinic acid (derived from birch bark), polysaccharides (beta-glucans), and superoxide dismutase (SOD) [1]. Chaga has the highest ORAC (oxygen radical absorbance capacity) score of any food tested [2]. Despite strong traditional use in Russian folk medicine and impressive in vitro data, human clinical trials are essentially absent [1].
2
Chaga
Inonotus obliquus
Conditionally SafeLimitedMushrooms
Clinical verdict: Chaga has the highest ORAC score and impressive preclinical data (betulinic acid, beta-glucans, melanin) — but essentially ZERO human clinical trials. It is the most hyped mushroom relative to its evidence base. High oxalate content poses kidney stone risk with raw tea consumption. All human health claims are extrapolated from lab studies [1] [2].
RDA
Typical 500–2,000 mg
Target
N/A
UL
No UL
Category
Mushrooms
Population dosing
🔗 Best with: Reishi, Turkey Tail, Birch bark extract✅ USP Verified, ConsumerLab Approved, USDA Organic
2 Risk self-assessment
Not applicable — not an essential nutrient [1]
Select factors above to see your risk level
Clinical pearl for practitioners
SupplementIndex
Chaga
Inonotus obliquus · Conditionally Safe · Evidence: Limited
RDA
Typical 500–2,000 mg
Upper limit
No UL
Evidence
Limited
Clinical bottom line
Chaga has the highest ORAC score and impressive preclinical data (betulinic acid, beta-glucans, melanin) — but essentially ZERO human clinical trials. It is the most hyped mushroom relative to its evidence base. High oxalate content poses kidney stone risk with raw tea consumption. All human health claims are extrapolated from lab studies [1] [2].
Do not miss
⚠ ZERO human clinical trials — all benefits are from in vitro/animal studies [1]
⚠ Oxalate nephropathy risk from daily raw chaga tea consumption [1]
⚠ Patient with kidney stone history — avoid raw chaga tea [1]
⚠ ORAC score is meaningless for health outcomes (USDA abandoned it in 2012) [2]
Pregnancy
No data. Avoid [1].
4 Dietary sources
mg
Consumed as tea or supplement [1].
5 Lab interpreter

No standard monitoring

<12 Deficient
12–20 Insufficient
20–50 Optimal
50–100 Excess
>150 Toxic
Your level:
Enter a value above
⚕ For healthcare professionals. Does not replace clinical judgment.
6 Quick facts
CategoryMushrooms
Safety levelConditionally Safe
EvidenceLimited
RDATypical 500–2,000 mg
Upper limit (UL)No UL
Scientific nameInonotus obliquus
SpeciesInonotus obliquus (Hymenochaetaceae) [1]
GrowthParasitic on birch trees; cold climates (Russia, Scandinavia, Canada) [1]
Active compoundsBetulinic acid, melanin, beta-glucans, SOD, polyphenols [1]
ORAC scoreHighest recorded for any natural substance [2]
Human clinical trialsEssentially NONE [1]
Typical dose500–2,000 mg/day extract [2]
7 Dosage by population

Adults Moderate

See product label

Elderly Moderate

See product label
Consider reduced renal/hepatic clearance. Start at lower end of range.

Pregnancy Moderate

See guidance
No data. Avoid [1].

Pediatric Moderate

See guidance
No data [1].

Athletes Limited

Standard dose

Obesity Limited

Standard dose
Fat-soluble compounds may require dose adjustment in obesity.

Renal Limited

Consult specialist
Dose adjustment may be needed in renal impairment.

Vegan Moderate

Standard dose
500–2,000 mg/day extract. Chaga contains very high oxalate content — potential kidney stone risk with regular consumption, especially as tea from raw chunks [1].
8 Form comparison
FormBioavailabilityVeganCost/day
['Hot water extract', 'common', 'Extracts water-soluble polysaccharides (beta-glucans). Most common preparation [1].']StandardCheck label
['Dual extract (water + alcohol)', 'preferred', 'Also captures betulinic acid and other triterpenes. More complete profile [1].']StandardCheck label
['Raw chaga chunks/powder', '', 'For tea decoction. Traditional Russian preparation [1].']StandardCheck label
9 Clinical evidence

Strong evidence

Highest ORAC score measured: extraordinary in vitro antioxidant capacity [2]. Betulinic acid has validated anti-cancer, anti-inflammatory, and antiviral properties in preclinical models [1]. Beta-glucan immunostimulation [1]. HIGH

Moderate evidence

Anti-inflammatory: reduced markers in animal models [1]. Anti-tumor: betulinic acid induces apoptosis in cancer cell lines [1]. Antiviral: activity against influenza, HIV, HSV in vitro [1]. MODERATE

Insufficient evidence

ALL human clinical indications — there are essentially NO human RCTs for chaga [1]. Cancer treatment/prevention in humans [1]. Diabetes [1]. Cardiovascular [1]. Immune enhancement in humans [1]. Anti-aging [1]. LOW
10 Safety

🚩 Red flags — when to stop and refer

● Daily raw chaga tea drinker with rising creatinine — oxalate nephropathy [1]
● Patient citing ORAC score as evidence — ORAC doesn't predict health outcomes [2]
● Patient using chaga for cancer treatment — no human evidence [1]

Pregnancy

No data. Avoid [1].

Pediatric

No data [1].
11 Toxicity and overdose

12 Drug interactions
Anticoagulants Moderate
Mechanism: Possible antiplatelet effects. [1]
Effect: Theoretical bleeding risk. [1]
Action: Monitor [1].
Insulin/diabetes medications Moderate
Mechanism: Blood glucose lowering in animal studies. [1]
Effect: Theoretical hypoglycemia. [1]
Action: Monitor glucose [1].
13 Supplement interactions

Best combined with

Other medicinal mushrooms (Reishi, Turkey Tail) · Standard doses of each
Different bioactive profiles; comprehensive mushroom stack [1].
14 Laboratory monitoring
No standard monitoring Primary
Target: N/A · N/A [1].
Monitor creatinine/GFR if regular raw chaga tea consumption [1].
Serum creatinine, urinalysis Secondary
Target: Normal · If daily chaga tea user [1].
15 Deficiency and prevalence
0%
[1]

Risk factors

• Not applicable — not an essential nutrient [1]
16 Frequently asked questions
Is chaga the most powerful antioxidant? ▼
It has the highest ORAC score measured, but ORAC is an in vitro assay that does not predict in vivo benefit [2]. ORAC was abandoned as a measure by the USDA in 2012 because it didn't correlate with health outcomes. Chaga's antioxidant potential is real but unproven in humans.
Are there any human studies on chaga? ▼
Essentially none. Despite enormous popularity and impressive preclinical data, chaga lacks human clinical trials [1]. This is a major gap — claims of human health benefits are based entirely on extrapolation from in vitro and animal studies.
Is chaga safe to drink daily? ▼
The major concern is oxalate content — chaga tea from raw chunks can provide very high oxalate loads, contributing to kidney stone risk. One case report described chaga-induced oxalate nephropathy [1]. Extracts with reduced oxalate are preferable for regular use.
Why does chaga grow on birch? ▼
Chaga is a parasitic fungus specific to birch trees. It incorporates betulinic acid from birch bark — this compound has anti-cancer and anti-viral properties. Only birch-grown chaga contains significant betulinic acid [1].
17 Regulatory status
Russia: Traditional medicine. Listed in Russian State Pharmacopoeia [1].
United States (FDA): Dietary supplement. No health claims [1].
Finland/Scandinavia: Traditional wild-harvested product. Growing commercial cultivation [1].
South Korea: Available as supplement.
18 References
[1]Glamočlija J, et al. Chemical characterization and biological activity of Chaga (Inonotus obliquus), a medicinal 'mushroom.' J Ethnopharmacol. 2015;162:323-332. doi:10.1016/j.jep.2014.12.069 REVIEW
[2]National Institutes of Health, MedlinePlus. Chaga Mushroom. Updated 2024. medlineplus.gov REVIEW
19 US supplement products
28
on-market US dietary supplements contain Chaga
Source: NIH Dietary Supplement Label Database (DSLD). Cross-referenced with SupplementIndex safety profiles.

Top brands

BioAnue7 products
New Chapter4 products
Country Farms2 products
Aurora NutraScience1 products
Country Life1 products
Garden of Life1 products
Good Pharma1 products
Herbal Terra1 products
Herbalist & Alchemist1 products
InfoWars M.D1 products

Product forms

Capsule (18)Liquid (4)Powder (4)Other (e.g. tea bag) (1)Tablet or Pill (1)

Sample products

Ultra-Liposomal C-Buster Aurora NutraScienceLiquid
Chaga Extract BioAnuePowder
Chaga Extract BioAnueCapsule
Chaga Extract BioAnueCapsule
Chaga Extract BioAnueCapsule
View all 28 products containing Chaga →
20 Frequently paired with
Ingredients most often found in the same supplement products as Chaga, based on NIH DSLD data.
Cordyceps
Conditionally Safe 9 shared products
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Chaga vs ReishiChaga vs Turkey Tail
22 Cite this page
Vancouver
Pkhakadze G. Chaga — safety profile [Internet]. Tbilisi: Public Health Institute of Georgia; 2026 [cited 2026 May 30]. Available from: https://supplement.ge/ingredients/chaga/
APA 7th
Pkhakadze, G. (2026). Chaga — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/chaga/
CC BY 4.0
🛡 SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
GP
Reviewed by Prof. G. Pkhakadze, MD, MPH, PhD
Editor-in-Chief, Georgian Medical Journal · Chair, PHIG
Last reviewed: May 2026 · Next: November 2026
This entry is provided for educational and public health purposes under CC BY 4.0. Consult your healthcare provider before starting any supplement. For corrections: info@accreditation.ge.
Publisher: PHIG · Editor-in-Chief: Prof. Giorgi Pkhakadze, MD, MPH, PhD