Chaga: What is it, how does it work, and what should you look out for?

Short answer: Chaga (Inonotus obliquus, called berkenweerschijnzwam in Dutch and chaga mushroom in English) is a fungus that grows as a hard, black lump on birch trees and is often called a chaga mushroom. It contains polysaccharides, polyphenols, triterpenes, and oxalate. Research into its effects has mainly been conducted in cell cultures and animals, and because of the oxalate, chaga is best taken at a fixed, limited daily dose.

Last updated: November 3, 2026 · Written by Florian Fermin

Chaga is the mushroom I take the most measured view of. It is popular, but human research is limited and it contains oxalate. So here we simply lay out what is known and what you really need to watch out for.

Chaga mushroom: what is it exactly, and where does it grow?

Chaga is a fungus that grows on living birch trees in cold regions such as Scandinavia, Russia, Siberia, and Canada. What is harvested is not a mushroom with a stem and cap. It is a sclerotium: a hard, black growth on the trunk with an orange-brown, cork-like interior.

A sclerotium is a compact mass of fungal threads that allows a fungus to survive. Chaga looks almost like a piece of charred wood. In Northern Europe and Russia, chaga was traditionally drunk as tea or as a coffee substitute.

Today, chaga is most commonly available as powder, capsules, or extract capsules.

What compounds are found in chaga?

Chaga contains four groups of compounds that play a role in research and safe use: polysaccharides such as beta-glucans, dark polyphenols and melanin, triterpenes such as betulin and inotodiol, and oxalate. These compounds do not all dissolve in the same things. So how you prepare chaga partly determines what you get from it.

Beta-glucans are chains of sugars from the cell walls of fungi and mushrooms. Oxalate is a salt of oxalic acid, which is also found in spinach and rhubarb and can bind to calcium in the body. Because oxalate dissolves in water, it also ends up in a hot drink made with chaga.

How does chaga work? What does research say?

Research into how chaga works has mainly been conducted in cell cultures and animals, focusing on antioxidants, polysaccharides, and triterpenes. Well-designed human studies are largely lacking. No health claims for chaga have been approved in the EU, and what happens in a lab does not automatically tell us what happens in your body.

Two review articles summarize the research (Lu et al., 2021, Ern et al., 2024). These are the topics that come up most often.

This research looks at the antioxidant activity of chaga extracts in the lab, how polysaccharides behave in cell models, and triterpenes such as betulin and inotodiol. This is interesting basic research, but the findings are still limited and have not been confirmed in humans.

Chaga is a dietary supplement, not a medicine. Since no health claims for chaga have been approved, we make no promises about what it does in your body. There simply isn’t any research in humans either.

What are the benefits of chaga?

The honest answer: we can’t promise you health benefits, because no health claims for chaga have been approved in the EU. What we can do is summarize what is known and what has (not yet) been demonstrated.

What is known:

• What it contains: polysaccharides (including beta-glucans), polyphenols and triterpenes (Ern et al., 2024), as well as oxalate.
• Nutritional value: the label on our chaga powder states 70.8 g of fiber per 100 g.
• How it’s used: in Northern Europe and Russia, chaga has traditionally been consumed as tea or as a coffee substitute.
• The main thing to watch: because of the oxalate, the amount per day matters.

What has not been demonstrated or established:

• That results from cell cultures and animal studies also apply to humans.
• An officially established daily dose: there isn’t one for chaga.
• The big promises about chaga you read online. There’s no good research in humans to support them, and they’re also not allowed in the EU.

My personal take: think of chaga as a mushroom you use for its flavor and tradition, with a consistent daily dose. Not as something that has to deliver on promises. If someone promises you major benefits from chaga, I’d take that with a grain of salt.

What should you watch out for with chaga, and why does oxalate matter?

Chaga naturally contains oxalate. Long-term use of large amounts can become a problem, so the main thing to watch with chaga is simply the amount. Little is known about other side effects, because there is no good research in humans.

So a consistent daily dose is more important with chaga than with most other mushrooms. Don’t use large amounts of chaga over a long period, and add up all the chaga you consume in a day.

Who should be extra cautious with chaga?

Consult your doctor or pharmacist first if you:

• have ever had kidney stones
• take medication, such as blood thinners
• are allergic to mushrooms or fungi
• are pregnant or breastfeeding

Chaga powder or chaga extract: what’s the difference?

Chaga powder and chaga capsules contain whole ground chaga, while chaga extract is concentrated. We offer chaga as powder, capsules, and extract capsules. Stir powder into a drink or smoothie; capsules provide a fixed amount without any taste, and the extract lists its beta-glucan and polysaccharide content.

What does 20:1 mean for chaga extract?

20:1 means that 20 parts dried chaga were used to make 1 part extract. So one 400 mg capsule contains extract made from approximately 8 g of dried chaga (400 mg x 20, calculated). This tells you how much starting material was used, not what effect it has. That’s why we also state the content: 20% beta-glucans and 30% polysaccharides. The extraction method used (water, alcohol, or both) is not (yet) specified for our chaga extract. Find out what a double extraction is and what a ratio like 20:1 does and doesn’t tell you in double extraction explained.

How do you use chaga powder?

According to the packaging, take 1-3 scoops (approximately 1-3 g) of chaga powder once a day, preferably during or just after a meal. Stir it into a smoothie, yogurt, coffee, or warm water. Ground chaga doesn’t dissolve completely, so a little sediment is normal. It’s best to measure in grams rather than teaspoons, since a teaspoon isn’t a fixed measure.

Can you drink chaga tea?

Yes, if you make it with chaga powder. We don’t recommend brewing tea from loose chaga pieces, because in the EU, chaga is considered a novel food when sold as a conventional food product (European Commission, 2024). Our chaga powder (a supplement) can simply be stirred into warm water, within a daily intake of 1-3 g. Find out how to make it and what it tastes like in our article about chaga tea.

How much chaga per day is sensible?

There is no officially established daily dose for chaga. Follow the daily dosage on the packaging, don’t use multiple chaga products at the same time, and don’t use large amounts of chaga over a long period. An extract is more concentrated than powder, so an extract capsule is not interchangeable with a powder capsule.

So I’d simply follow the directions on the packaging and, if in doubt, check with your doctor first.

What does the packaging say about GOYU chaga?

We sell chaga as organic powder, organic 500 mg capsules, and extract capsules, all from Inonotus obliquus. The extract is 20:1, with 400 mg of extract per capsule, of which 20% is beta-glucans and 30% is polysaccharides. Each package includes specific directions for use, so you know how much to take each day. We have a certificate of analysis (CoA) for every batch.

• Chaga powder (60 g, organic): "Take 1-3 scoops (about 1-3 g) daily." and "Mix the powder into a smoothie, yogurt, or another preparation." At 1 to 3 g per day, one bag (60 g divided by 3 g = 20 days, 60 g divided by 1 g = 60 days) lasts 20 to 60 days.
• Chaga capsules (500 mg, organic): "Take 1-3 Chaga capsules once a day." That’s 500 to 1500 mg of chaga per day.
• Chaga extract capsules (400 mg): "Take 1 capsule, 1 to 2 times a day."

As for nutritional value: Chaga is naturally high in fibre**

**Approved health claim (Regulation (EU) No 432/2012) or nutrition claim (Regulation (EC) No 1924/2006).

Reviews on getgoyu.com (Judge.me, October 2026) give the chaga powder an average rating of 5.0 from 13 reviews, the capsules 4.82 from 17 reviews, and the extract capsules 4.6 from 10 reviews. Customers describe the powder’s taste as earthy. To see the CoA for a batch, just request it via support@getgoyu.com.

What should you look for when buying chaga?

When buying chaga, look for four things: whether it’s genuine birch chaga or mycelium grown on grain, whether the origin and harvest are clearly stated, whether there is a certificate of analysis for heavy metals and microbiology, and, for extracts, the extraction method and a stated content.

• Sclerotium of mycelium: true chaga is the birch tree’s burl. There are also products made with mycelium grown on grain. These often consist largely of grain starch. Read more in fruiting body or mycelium.
• Origin and harvesting: chaga grows slowly. Choose a supplier that is transparent about its origin and sustainable harvesting.
• Lab testing: a certificate of analysis (CoA) showing heavy metals and microbiology. Here's how to read one: CoA for a mushroom supplement.
• Extraction method and content: for extracts, check the ratio and, ideally, a stated beta-glucan or polysaccharide content.

Customers also sometimes ask us where our mushrooms come from and whether they contain lead. Our raw materials come from China, which is exactly why I always check the heavy metals on the CoA.

If you want to compare chaga with other brands, use the 7 criteria in our article about choosing the best mushroom supplement.

Can you combine chaga with reishi or lion's mane?

Chaga is often used alongside reishi, lion's mane, or cordyceps. Each contains different compounds, and they are not interchangeable, so one does not replace another. When combining them, make sure you don't unknowingly use multiple sources of chaga at once, for example, powder and capsules.

Also read our article about reishi and lion's mane, or explore all forms in our mushroom collection.

Summary in 3 points

• Chaga (Inonotus obliquus) is a hard fungal growth on birch trees containing polysaccharides, polyphenols, triterpenes, and oxalate.
• Research has mainly been conducted in cell cultures and animals. There is hardly any good research in humans, and there are no approved health claims.
• Because of its oxalate content, it's important to stick to a fixed daily dose. Follow the packaging instructions and consult your doctor first if in doubt.

Frequently asked questions

What is chaga?

Chaga (Inonotus obliquus) is a fungus that grows as a hard, black lump on birch trees in cold regions. Traditionally, it was drunk as a tea in Northern Europe and Russia.

What are the effects of chaga?

Research on the effects of chaga has mainly been conducted in cell cultures and test animals. They have not been demonstrated in humans, and there are no approved health claims for chaga in the EU. We therefore make no promises about its effects.

What does chaga taste like?

Earthy and mild, sometimes slightly vanilla-like. Chaga is less bitter than reishi.

Does chaga have side effects?

Chaga contains oxalate, and long-term use of large amounts can become a problem. Follow the daily dose and consult your doctor if you take medication or have ever had kidney stones.

Can you drink chaga in warm water every day?

There is no research establishing a safe daily amount of chaga. Stay within the daily dose on the packaging (for our powder, 1-3 g per day), count all the chaga you consume that day, and consult your doctor if you take medication or have any concerns.

Is chaga powder or extract better?

Powder is the whole ground chaga and can be used in many ways. An extract is more concentrated. So it simply depends on your routine.

How much chaga powder should you take per day?

According to the packaging, take 1-3 scoops (approximately 1-3 g) once a day, mixed into a smoothie, yogurt, coffee, or warm water. Do not take it at the same time as other chaga products, so you know how much chaga you are consuming that day.

Is chaga allowed in supplements in the EU?

Yes. Chaga is permitted in dietary supplements in the EU. However, as a regular food, such as loose chaga tea, chaga is considered a novel food (European Commission, 2024).

Sources

1. Lu Y, Jia Y, Xue Z, Li N, Liu J, Chen H. Recent Developments in Inonotus obliquus (Chaga mushroom) Polysaccharides: Isolation, Structural Characteristics, Biological Activities and Application. Polymers (Basel). 2021;13(9):1441. Europe PMC 33947037
2. Ern PTY, Quan TY, Yee FS, Yin ACY. Review article on Inonotus obliquus (chaga). Mycology. 2024;15(2):144-161. Europe PMC 38813471
3. Customer reviews of chaga powder, capsules, and extract capsules on getgoyu.com. Judge.me, October 2026.
4. European Commission. Consultation process on novel food status: Chaga (Inonotus obliquus). Receiving Member State: Finland (Finnish Food Authority). Published November 14, 2024. food.ec.europa.eu (PDF)
5. GOYU, labels for Chaga Powder, Chaga Capsules, and Chaga Extract Capsules (ingredients, nutritional information, and directions for use), 2026.

You can find all forms of our chaga on the buy chaga page.

This article is for informational purposes only and is not medical advice. Dietary supplements are not a substitute for a varied, balanced diet and a healthy lifestyle. If in doubt, during pregnancy, or if you take medication, consult your doctor or pharmacist.