Ingredient Guide
Chaga Explained: The Birch Fungus and What We Know
Chaga (Inonotus obliquus) is a charcoal-like fungus that grows on birch trees. What it contains, what the research does and does not show, the oxalate caution, and how it fits into Forage.
Explore Mushroom SupportChaga on the Label
Exactly how much chaga is in our product, straight from the label.
How to use it (label directions): follow the directions on the Forage label. Each bottle holds 30 servings. How this compares with research doses: there is no established human dose for chaga, because it has not been tested in controlled trials in healthy people. Forage contains 150 mg of an 8:1 chaga extract as one of seven mushrooms, a small amount compared with the teaspoons of powder some people take as tea. Use it as directed on the label.
A Fungus From the Birch Forest
Chaga (Inonotus obliquus) is a fungus that grows on living birch trees across the cold forests of Russia, Scandinavia, Canada and the northern United States. The part people harvest is not a soft mushroom but a hard, black, cracked growth called a sclerotium or conk, which looks like burnt charcoal on the outside and is rusty orange inside.
Chaga has a long history as a folk tea in Russia and northern Europe. Today it is popular in mushroom coffees and blends. We include 150 mg of an 8:1 chaga extract in Forage, our seven mushroom blend, alongside turkey tail, reishi, cordyceps and lion's mane.
Tip: Chaga has the least human research of the mushrooms in Forage. Its value is in its compounds and laboratory findings, not proven results in people.
What Is in Chaga
Chemical studies of chaga have identified several groups of active compounds.
Melanins and Phenolic Compounds
The dark color of chaga comes from melanin pigments, which, along with its phenolic compounds, give it strong antioxidant activity in laboratory tests.
Triterpenoids and Betulin
Chaga contains lanostane-type triterpenoids such as inotodiol, and it concentrates betulin and betulinic acid from the birch bark it grows on.
Polysaccharides
Like other medicinal fungi, chaga contains polysaccharides, including beta-glucans, which interact with immune cells in laboratory studies.
What These Compounds Do in the Lab
Reviews of the preclinical research describe antioxidant effects, activation of immune signaling, and lower blood sugar and better insulin sensitivity in animal models. These are mechanisms, not proven outcomes in people.
What the Research Shows
The research on chaga is almost entirely in cells and animals. A 2021 review tracing chaga from folk medicine to clinical use describes promising laboratory findings, particularly for blood sugar handling, immune signaling and antioxidant defense, and a 2019 review of the preclinical studies describes the likely mechanisms. We found no controlled trials of chaga in healthy people.
That is why we describe chaga as a supporting mushroom with strong antioxidant chemistry, rather than making claims about specific benefits in people.
The honest summary: chaga is rich in antioxidant compounds and has an interesting laboratory profile, but no controlled human trials yet. It is one of seven mushrooms in Forage, used at a small amount alongside better studied mushrooms such as turkey tail, reishi and lion's mane.
Chaga and Other Forage Mushrooms
Forage combines seven mushrooms. Here is how chaga compares with two of its neighbors.
| Feature | Chaga | Turkey tail | Reishi |
|---|---|---|---|
| What is harvested | Sclerotium (conk) on living birch | Fan-shaped fruiting body on dead wood | Glossy fruiting body |
| Key compounds | Melanins, phenolics, triterpenoids, betulin | PSP and PSK polysaccharides | Triterpenes, beta-glucans |
| Human trials | None controlled in healthy people | Gut microbiome trial in healthy volunteers | Several small trials |
| In Forage | 150 mg 8:1 extract | 150 mg 8:1 extract | 200 mg 8:1 extract |
Dosage, Timing, and Stacking
Amounts
There is no established human dose for chaga. Forage provides 150 mg of an 8:1 extract per serving, a small amount, so follow the label.
Timing
Follow the directions on the Forage label.
Stacking
Chaga already sits with six other mushrooms, Himalayan shilajit and ashwagandha root extract in Forage. If you also drink chaga tea or a mushroom coffee that contains chaga, count it in your total because of the oxalate content. See mushroom coffee vs regular coffee for more on those products.
Safety and Side Effects
Chaga has a long history of use as a tea, but it needs more care than most mushrooms.
Points Worth Knowing
- Oxalates and the kidneys: chaga is very high in oxalates. A published case report described serious kidney damage from oxalate buildup in a woman who took 4 to 5 teaspoons of chaga powder a day for six months. People with kidney problems or a history of kidney stones should avoid concentrated chaga.
- Blood sugar: chaga lowered blood sugar in animal studies, so people taking glucose-lowering medication should ask their clinician first.
- Blood clotting: laboratory studies suggest chaga may slow blood clotting, so people taking blood thinners, or preparing for surgery, should ask first.
Who should be cautious: speak with a qualified healthcare professional before using chaga if you are pregnant or nursing, have a kidney condition or kidney stones, take glucose-lowering or blood-thinning medication, have an autoimmune condition, or take any other regular medication.
Key Takeaways
- Chaga (Inonotus obliquus) is a birch fungus harvested as a hard black sclerotium.
- It is rich in melanins, phenolics, triterpenoids and betulin with strong antioxidant activity in the lab.
- There are no controlled trials in healthy people, so its benefits in humans are unproven.
- It is very high in oxalates; large intakes have been linked with kidney damage.
- Forage contains 150 mg of an 8:1 chaga extract per serving, alongside six other mushrooms.
Respect the Birch Fungus.
Chaga brings rich antioxidant chemistry and a long folk history. We use a small amount alongside better studied mushrooms, and we are clear about what the research does and does not show.
Chaga FAQ
What does chaga mushroom do for you?
Chaga (Inonotus obliquus) is rich in melanins, phenolic compounds and triterpenoids with strong antioxidant activity in laboratory tests. Cell and animal studies also show effects on immune signaling and blood sugar. There are no controlled trials in healthy people yet, so its benefits in humans are still unproven.
Who should not take chaga?
Chaga is very high in oxalates, so people with kidney problems or a history of kidney stones should avoid concentrated chaga products. Because it may lower blood sugar and slow blood clotting in laboratory studies, people taking glucose-lowering or blood-thinning medication should ask a clinician first, as should anyone who is pregnant or nursing.
Is chaga hard on your kidneys?
It can be at high intakes. Chaga contains very high levels of oxalate, and a published case report described kidney damage in a woman who had taken 4 to 5 teaspoons of chaga powder a day for six months. That is far more than the 150 mg of extract in a serving of Forage, but it is the reason to respect the dose.
Is chaga psychedelic?
No. Chaga contains no psychoactive compounds and does not cause psychedelic effects.
Is chaga a real mushroom?
Chaga is a fungus, but the part that is harvested is not a typical cap-and-stem mushroom. It is a hard, black, charcoal-like growth called a sclerotium or conk that forms on living birch trees.
How much chaga is in Forage?
Each 2-capsule serving of Forage contains 150 mg of an 8:1 chaga extract, alongside lion's mane, cordyceps, reishi, maitake, turkey tail, shiitake, Himalayan shilajit and ashwagandha root extract.
More on Chaga
Related guides
Sources
- Szychowski KA, et al. Inonotus obliquus: from folk medicine to clinical use. Journal of Traditional and Complementary Medicine, 2021. PubMed 34195023
- Duru KC, et al. The pharmacological potential and possible molecular mechanisms of action of Inonotus obliquus from preclinical studies. Phytotherapy Research, 2019. PubMed 31209936
- Zheng W, et al. Chemical diversity of biologically active metabolites in the sclerotia of Inonotus obliquus and submerged culture strategies for up-regulating their production. Applied Microbiology and Biotechnology, 2010. PubMed 20532760
- Balandaykin ME, et al. Review on Chaga medicinal mushroom, Inonotus obliquus (Higher Basidiomycetes): realm of medicinal applications and approaches on estimating its resource potential. International Journal of Medicinal Mushrooms, 2015. PubMed 25746615
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Nothing here is medical advice. If you are pregnant, nursing, taking medication (especially glucose-lowering or blood-thinning medication), or managing a kidney or other health condition, consult a qualified healthcare professional before use.