Home Ingredients Chaga Mushroom (Inonotus obliquus)
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Chaga Mushroom (Inonotus obliquus)

Inonotus obliquus
Evidence Level
Preliminary
3 Clinical Trials
5 Documented Benefits
1/5 Evidence Score

Chaga is a parasitic fungus that grows on birch trees in cold climates — used in Russian, Korean, and Eastern European traditional medicine for centuries. Distinguished by a high concentration of melanin, betulinic acid (from birch bark), and beta-glucan polysaccharides. Studied for antioxidant effects, immune support, anti-inflammatory, and anti-cancer research. Critical caution: chaga is extremely high in oxalate. One analysed sample contained 14.2 g of oxalate per 100 g of powder. Published case reports describe oxalate nephropathy requiring dialysis after about six months of daily use, and end-stage renal disease after years of use. Anyone with kidney disease, reduced kidney function, or a history of kidney stones should avoid chaga rather than moderate it. Note also that human efficacy evidence is essentially absent: no clinical trial has tested chaga on its own in people, so everything below rests on laboratory and animal work.

Studied Dose 500 to 2,000 mg/day of extract, or 3 to 4 g of dried chaga per cup of tea. That much dried chaga is high in oxalate, so avoid it if you have kidney disease or kidney stones.
Active Compound Beta-glucans, betulinic acid, melanin, polyphenols, triterpenes (inotodiol, lanosterol)

Benefits

Antioxidant Activity

Chaga is marketed on its very high ORAC (oxygen radical absorbance capacity) score, but ORAC is only a test-tube reaction between an extract and a synthetic free radical and predicts nothing about what happens in the body. The USDA removed its ORAC database in May 2012, stating that the values have no demonstrated relevance to the effects of bioactive compounds on human health and that they were routinely misused to market foods and supplements. A high ORAC number for chaga is therefore a fact about a chemistry assay, not a health benefit. Active compounds include polyphenols, melanin, and various phenolic compounds. In the laboratory study cited on this page, a polyphenol-rich chaga extract scavenged free radicals and protected cultured human skin cells from peroxide damage, while the polysaccharide fraction was inactive. There is no clinical translation to describe: no human trial has measured whether swallowing chaga changes any antioxidant marker in the body.

Supported by Trial 1

Immune Modulation

Beta-glucans activate innate immune cells (macrophages, NK cells, dendritic cells) — similar mechanism to other medicinal mushrooms. This is cell culture evidence. In the study cited on this page the active fractions were water-soluble polysaccharides acting through Toll-like receptors 2 and 4, while the classic particulate beta-glucan from chaga acted on Dectin-1 and did not trigger those macrophage functions, so the popular beta-glucan explanation is not what the data actually show. No human trial has measured any immune outcome, such as infection rates, vaccine response or immune cell counts, in people taking chaga.

Supported by Trial 2, Trial 3

Anti-Inflammatory Effects

Reduces inflammatory cytokines and oxidative stress markers in animal models. There is no human evidence. No clinical trial has measured inflammatory markers, or any symptom of inflammation, in people taking chaga.

Supported by Trial 3, Trial 1

Anti-Cancer Research

Extensive in vitro evidence for cancer cell apoptosis induction — particularly betulinic acid (concentrated in chaga from birch). Animal models supportive. There is no human clinical translation at all. No clinical trial has tested chaga in people with cancer, for any cancer, at any dose. Chaga is not a cancer treatment and must never be used in place of oncology care, or alongside it without the treating oncologist knowing. This is not a theoretical caution. In the first published case of chaga-induced oxalate nephropathy the patient was a woman with liver cancer taking chaga powder daily for that cancer, and she ended up on hemodialysis.

Supported by Trial 3

Blood Sugar Modest Effects

One study in alloxan-diabetic mice found that chaga water extract at 500 mg/kg lowered fasting glucose, improved glucose tolerance and improved lipids over four weeks. That is a mouse dose in a chemically induced model of diabetes, and there is no human clinical evidence at all. Chaga should not be used to manage blood sugar. Anyone taking diabetes medication should treat a possible glucose-lowering effect as an interaction risk to monitor rather than a benefit to seek.

Supported by Trial 3, Trial 1

Mechanism of action

1

Beta-Glucan Immune Activation

Beta-1,3 and beta-1,6 glucans bind to dectin-1 receptors on immune cells, activating innate immune responses. That is the standard account for medicinal mushroom beta-glucans, but the chaga study cited on this page complicates it. The fractions that actually activated macrophages were water-soluble polysaccharides working through Toll-like receptors 2 and 4, while the particulate beta-glucan that binds Dectin-1 did not produce those effects. All of this is cell culture and mouse work, not evidence of an immune effect in people.

2

Betulinic Acid (From Birch)

Betulinic acid is concentrated in chaga because the fungus parasitizes birch trees and accumulates birch bark compounds. Has antiviral, anti-inflammatory, and apoptosis-inducing effects in vitro. Two limits are worth stating. The betulinic acid content of a chaga product is not standardized, since supplements are standardized to beta-glucan rather than to betulinic acid and wild-harvested material varies. And betulinic acid is poorly water soluble, which is why research on it relies on structural derivatives and nanoformulations to improve bioavailability. Effects produced in a dish at controlled concentrations should not be assumed to follow from drinking chaga tea.

3

Melanin Antioxidant

Chaga's distinctive black appearance comes from high melanin content — natural pigment with antioxidant properties. Chaga melanin is measurable in the laboratory, but ORAC and similar test-tube antioxidant scores do not predict effects in the body, and there is no evidence that melanin from chaga is absorbed intact when it is swallowed.

4

Triterpene Bioactivity

Inotodiol, lanosterol and other triterpenes show anti-inflammatory and pathway-modulating effects in cell and animal experiments. None of this has been followed up in a human trial, so it describes what chaga might plausibly do rather than anything it has been shown to do in a person.

Clinical trials

1
Antioxidant Activity (Preclinical)
PubMed

In vitro and cell-based studies of Inonotus obliquus extract, including Cui et al. (J Ethnopharmacol, 2005).

Cell cultures and isolated tissues. No human trials.

Chaga extract shows strong antioxidant activity in the laboratory, scavenging free radicals and protecting cells from oxidative damage. These results come from test-tube and cell models. No human clinical trials have tested chaga for antioxidant outcomes. In the 2005 study the polyphenol fraction did the work while the polysaccharide fraction was inactive, and the cells were cultured human skin cells with extract applied directly to them, not cells reached through a digestive tract.

2
Immune Activation (Preclinical, Mechanistic)
PubMed

Mechanistic study of Inonotus obliquus polysaccharides on immune cells (Wold et al., Commun Biol, 2024).

Immune cell cultures. No human trials.

Chaga beta-glucans and polysaccharides act on Toll-like receptors and can activate macrophages in laboratory models, the proposed basis for its immune-modulating reputation. This is cell-based mechanistic evidence, not a human trial.

3
Anti-Cancer Research (Preclinical, Not a Treatment)

In vitro and animal studies of chaga extracts and the triterpene betulinic acid, summarized in mechanistic reviews.

Cancer cell lines and animal models. No human trials.

Chaga compounds such as betulinic acid trigger apoptosis in cancer cell lines and slow tumor growth in animals. Critically, there are no human clinical trials, chaga is not a cancer treatment, and marketing claims far exceed the evidence. People with cancer should also know that chaga's oxalate load is a documented hazard in this exact group. The first published case of chaga-induced oxalate nephropathy was a woman taking chaga powder daily for liver cancer who required hemodialysis.

Side effects and drug interactions

Common Potential side effects

Oxalate nephropathy and kidney stones. This is the most serious documented risk of chaga and it is not merely theoretical. Chaga is extremely high in oxalate, measured at 14.2 g per 100 g of powder in one analysed sample. Three published human cases: a 72-year-old Japanese woman taking 4 to 5 teaspoons of chaga powder daily for six months for liver cancer developed oxalate nephropathy and required hemodialysis; a 49-year-old Korean man who used chaga powder long term for atopic dermatitis developed end-stage renal disease with oxalate crystal deposits on biopsy; and a 69-year-old man taking 10 to 15 g of chaga daily with 500 mg of vitamin C for three months developed acute kidney injury presenting as nephrotic syndrome, requiring dialysis and steroids, with recovery after a month. A rat study has since reproduced oxalate crystal deposition and kidney injury with high-dose chaga powder. One detail deserves emphasis: in the end-stage renal disease case the estimated oxalate intake was only about twice a usual diet for four years and five times for one year, so chronic moderate use, not just extreme use, is implicated. Vitamin C is partly metabolized to oxalate and should not be taken in high doses alongside chaga. Anyone with kidney disease, reduced kidney function, or a history of kidney stones should avoid chaga entirely.
Bleeding risk — modest antiplatelet effects.
GI distress at high doses.
Hypoglycemia in sensitive individuals.
Allergic reactions rare.
Mold/mycotoxin contamination possible in poorly-sourced products.

Important Drug interactions

Anticoagulants (warfarin, DOACs) — additive bleeding risk; this concern is theoretical. It rests on antiplatelet activity found in laboratory studies of chaga, and no published case describes chaga raising INR in a person; the case report usually quoted for that involves maitake, a different mushroom. Treat it as a precaution rather than a documented human interaction, and do not combine without medical supervision.
Antiplatelet drugs — additive bleeding risk.
Insulin / diabetes medications — modest hypoglycemic effect; monitor.
Immunosuppressants — chaga's immune activation could theoretically interfere; consult.
Pre-surgery, discontinue 2 weeks before. High-dose vitamin C, which the body converts in part to oxalate, should not be combined with chaga: in one published case of chaga-related kidney injury the patient was taking 500 mg of vitamin C daily alongside it.

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Frequently asked questions about Chaga Mushroom (Inonotus obliquus)

How much chaga should I take?

Common label amounts are around 1 to 3 grams per day of chaga extract or powder, but no human trial has established a dose, so these are traditional and marketing amounts rather than tested ones. The more important number is oxalate. Chaga powder has been measured at 14.2 g of oxalate per 100 g, so a few grams a day can supply several times the oxalate of an entire normal diet, and the published cases of kidney damage involved daily use in roughly this range or higher. If you have any kidney problem or a history of kidney stones, the right amount is none.

What is chaga used for?

Chaga is a mushroom that grows on birch trees, used traditionally in Russia, Korea and Eastern Europe for immune support and general wellness. Its modern reputation rests on test-tube antioxidant scores and laboratory immune studies. Human research is not merely limited, it is essentially absent: no clinical trial has tested chaga on its own in people, so claims about what it does should be treated as unproven.

Does chaga contain oxalates?

Yes, and this is the main safety issue with chaga. One analysed sample contained 14.2 g of oxalate per 100 g of powder, which is extremely high for anything people consume daily. Published case reports describe oxalate nephropathy requiring dialysis after about six months of daily use, and end-stage renal disease after long-term use where the estimated oxalate intake was only about twice that of a normal diet. People with a history of kidney stones or any kidney disease should avoid chaga rather than simply keep intake moderate.

Is chaga safe?

Occasional moderate use is generally well tolerated, but chaga carries a documented serious risk that most supplements do not: its very high oxalate content has caused kidney damage in published cases, including dialysis after about six months of daily powder and end-stage renal disease after years of use. Anyone with kidney disease, reduced kidney function, or a history of kidney stones should avoid it. Anyone taking blood thinners or diabetes medication should check with a doctor first, and high-dose vitamin C should not be taken alongside chaga.

What is Chaga Mushroom?

Chaga is a parasitic fungus that grows on birch trees in cold climates — used in Russian, Korean, and Eastern European traditional medicine for centuries. Distinguished by a high concentration of melanin, betulinic acid (from birch bark), and beta-glucan polysaccharides.

What is Chaga Mushroom used for?

Chaga Mushroom is researched primarily for Immune Support and Antioxidant. Chaga is marketed on its very high ORAC (oxygen radical absorbance capacity) score, but ORAC is only a test-tube reaction between an extract and a synthetic free radical and predicts nothing about what happens in the body.

What is the recommended dosage of Chaga Mushroom?

The clinically studied dose is 500 to 2,000 mg/day of extract, or 3 to 4 g of dried chaga per cup of tea. That much dried chaga is high in oxalate, so avoid it if you have kidney disease or kidney stones. Always follow the product label and check with a healthcare provider for personal advice.

Is Chaga Mushroom safe, and does it have side effects?

For most healthy adults, Chaga Mushroom is well tolerated at studied doses. Reported effects can include: Oxalate nephropathy and kidney stones. This is the most serious documented risk of chaga and it is not merely theoretical. Chaga is extremely high in oxalate, measured at 14.2 g per 100 g of powder in one analysed sample. It may also interact with some medications. Chaga Mushroom is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Chaga Mushroom interact with any medications?

Possible interactions include: Anticoagulants (warfarin, DOACs) — additive bleeding risk; this concern is theoretical. It rests on antiplatelet activity found in laboratory studies of chaga, and no published case describes chaga raising INR in a person; the case report usually quoted for that involves maitake,… If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Chaga Mushroom?

NutraSmarts rates the evidence for Chaga Mushroom as Preliminary (1 out of 5). It is backed by 3 clinical trials and 12 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(12 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Cui Y, Kim DS, Park KC. Antioxidant effect of Inonotus obliquus. J Ethnopharmacol. 2005;96(1-2):79-85. doi: 10.1016/j.jep.2004.08.037.PubMedUsed to support: Four chaga extracts were tested against DPPH, superoxide and peroxyl radicals, and on cultured human skin cells exposed to hydrogen peroxide. The polyphenol fraction scavenged radicals and protected the cells, while the polysaccharide, triterpenoid and steroid fractions did not. This is a test-tube and cell-culture study with extract applied directly to cells, so it cannot show what happens when a person swallows chaga. It is nonetheless the entire basis for the antioxidant claims made on this page.
  2. Wold CW, Christopoulos PF, Arias MA, Dzovor DE, et al. Fungal polysaccharides from Inonotus obliquus are agonists for Toll-like receptors and induce macrophage anti-cancer activity. Commun Biol. 2024;7(1):222. doi: 10.1038/s42003-024-05853-y.PubMedUsed to support: Six polysaccharides isolated from chaga were screened on mouse and human macrophages. Two water-soluble fractions activated macrophages through Toll-like receptors 2 and 4, drove cytokine release and inhibited cancer cell growth in culture and in mice, while the particulate beta-glucan fraction, which acts on Dectin-1, did not trigger those functions. This is cell and mouse work rather than a human trial, and it also argues that the popular beta-glucan explanation for chaga's immune reputation is the wrong mechanism.
  3. Delgersaikhan N, Odkhuu E, Khaltar P, Samdan E, et al. Antidiabetic activity of Inonotus obliquus water extract in alloxan-induced diabetic mice. J Complement Integr Med. 2024;21(4):472-480. doi: 10.1515/jcim-2024-0316.PubMedUsed to support: Animal study (diabetic mice) in which chaga water extract modestly lowered blood glucose. Supports the modest blood-sugar benefit at a preclinical level only; no human evidence.
  4. Gao Y, Wang D, Zheng Y, Sun H. Betulinic acid and apoptosis-involved pathways: Unveiling its bidirectional regulatory role. Eur J Pharmacol. 2025;1008:178361. doi: 10.1016/j.ejphar.2025.178361.PubMedUsed to support: Review of how betulinic acid regulates apoptosis, promoting cell death in cancer cells while protecting normal cells from oxidative stress. The limitation is important: this concerns purified betulinic acid at controlled laboratory concentrations, not chaga, and the review notes that structural derivatives and nanoformulations are used to improve the compound's bioavailability and tumor selectivity. It supports a mechanism, not a benefit of taking chaga, and chaga is not a cancer treatment.
  5. Ern PTY, Quan TY, Yee FS, Yin ACY. Therapeutic properties of Inonotus obliquus (Chaga mushroom): A review. Mycology. 2024;15(2):144-161. doi: 10.1080/21501203.2023.2260408.PubMedUsed to support: Review summarizing chaga's reported antioxidant, immune, anti-inflammatory, and antidiabetic properties, noting that most evidence is preclinical and human data are limited.
  6. Wang Y, Gu J, Wu J, Xu Y, et al. Natural Products and Health Care Functions of Inonotus obliquus. Curr Issues Mol Biol. 2025;47(4):269. doi: 10.3390/cimb47040269.PubMedUsed to support: Recent review of chaga's bioactive compounds (polysaccharides, triterpenes, polyphenols) and their proposed health functions, drawn largely from laboratory and animal research.
  7. Kikuchi Y, Seta K, Ogawa Y, et al. Chaga mushroom-induced oxalate nephropathy. Clin Nephrol. 2014;81(6):440-4..PubMedUsed to support: A 72-year-old Japanese woman took 4 to 5 teaspoons of chaga mushroom powder daily for six months while being treated for liver cancer. Her kidney function declined until hemodialysis was required, and a kidney biopsy showed diffuse tubular atrophy, interstitial fibrosis and oxalate crystals in the tubular lumina. This was the first published case of oxalate nephropathy associated with chaga. A single uncontrolled case cannot establish how common the risk is, and this intake was well above a typical capsule dose, but it is direct human evidence behind the kidney warnings given in the safety section.
  8. Lee S, Lee HY, Park Y, et al. Development of End Stage Renal Disease after Long-Term Ingestion of Chaga Mushroom: Case Report and Review of Literature. J Korean Med Sci. 2020;35(19):e122..PubMedUsed to support: A 49-year-old Korean man who had taken chaga mushroom powder long term for intractable atopic dermatitis presented with end-stage renal disease, and biopsy showed chronic tubulointerstitial nephritis with oxalate crystal deposits. His remaining chaga powder was analysed and contained 14.2 g of oxalate per 100 g, and his estimated oxalate intake was about twice that of a usual diet for four years and five times for one year. The intake was therefore sustained rather than extreme, which is why this case matters for ordinary daily users. It remains a single case report rather than a trial, and it is the source of the oxalate figure quoted elsewhere on this page.
  9. Kwon O, Kim Y, Paek JH, et al. Chaga mushroom-induced oxalate nephropathy that clinically manifested as nephrotic syndrome: A case report. Medicine (Baltimore). 2022;101(10):e28997..PubMedUsed to support: A 69-year-old man taking 10 to 15 g of chaga daily together with 500 mg of vitamin C for three months developed acute kidney injury that presented clinically as nephrotic syndrome, with calcium oxalate crystal deposition, focal acute tubular injury and minimal change disease on biopsy. He required hemodialysis and high-dose steroids, and kidney function recovered within a month of treatment. Vitamin C is itself partly metabolized to oxalate, so the combination compounds the load. This is a single uncontrolled case, but it supports both the kidney warning and the vitamin C caution in the safety section.
  10. Lee S, Cui S, Fang X, et al. Kidney Injury Induced by High-Dose Chaga Mushroom Consumption: Experimental Evidence in a Rat Model. J Korean Med Sci. 2026;41(3):e37..PubMedUsed to support: Rats given high-dose chaga powder, about 3,845 mg/kg of body weight supplying roughly 549 mg/kg of oxalate, developed oxalate crystal deposition in the kidney tubules along with raised urinary protein, increased oxidative stress and apoptosis markers and lower body weight. This is an animal study at a dose far above ordinary human use and it says nothing about what a normal capsule dose does in a person. Its value is that it supports the human case reports by showing that the oxalate content of chaga, rather than some coincidental factor, is what damages the kidney.
  11. Hong YH Effects of the herb mixture, DTS20, on oxidative stress and plasma alcoholic metabolites after alcohol consumption in healthy young men. Integr Med Res. 2016;5(4):309-316..PubMedUsed to support: Twenty healthy nonsmoking men aged 21 to 30 took a single dose of a four-herb mixture or a placebo in a crossover trial with a one-week washout, 30 minutes before drinking a bottle of soju. Plasma alcohol was lower and antioxidant activity higher two hours after drinking compared with placebo. This cannot be used as evidence for chaga. Chaga was only the third largest component of the formula at 20 percent, behind mistletoe at 40 percent and wolfberry at 30 percent, with eleuthero making up the rest, and the study measured alcohol metabolism after a single dose rather than any outcome claimed on this page. It is listed because it is one of only two published studies in which people swallowed anything containing chaga at all, which is why the evidence rating on this page treats chaga as having no human trial of its own.
  12. Najafzadeh M, Reynolds PD, Baumgartner A, et al. Chaga mushroom extract inhibits oxidative DNA damage in lymphocytes of patients with inflammatory bowel disease. Biofactors. 2007;31(3-4):191-200..PubMedUsed to support: Blood lymphocytes were collected from 20 people with inflammatory bowel disease and 20 healthy volunteers, then exposed to hydrogen peroxide in the laboratory with and without an ethanolic chaga extract added directly to the cells. The extract cut oxidative DNA damage by about 55 percent in the patient cells and about 35 percent in the healthy cells. Nobody swallowed anything in this study: the chaga was applied to cells in a dish, so it shows that the extract can protect human cells on contact, not that drinking chaga protects a person. It is the closest thing to human material behind the antioxidant claims on this page, and it is still a laboratory result.