Chaga mushroom: what you need to know

On the trunk of a birch tree, a black, cracked mass that looks like burnt wood: that is chaga. Popular as a tea and a powder, it is often marketed as a cure-all. The reality is more nuanced. Here is what the chaga mushroom really is, how it is harvested, how chaga tea is made, what researchers are studying and why it calls for some caution.

What is the chaga mushroom?

Chaga, Latin name Inonotus obliquus, is a fungus that infects living trees, mostly birch. It is found in Russia, Scandinavia, the Baltic states, Canada and the northern United States. It also occurs in central Europe, but is much rarer there.

A distinctive appearance

What is sold as chaga is a hard, irregular growth called a sclerotium that pushes out through the bark. The outside is black, fissured and almost charcoal-like. The inside is rusty brown to orange, with a corky texture. This part does not produce spores: chaga's true fruiting body forms later, under the bark, often after the tree has died.

The birch connection

Chaga grows slowly over several years at the expense of its host tree. Part of the interest in it comes from this relationship: it contains compounds derived from birch, such as betulin and betulinic acid. Chaga harvested from other tree species may not have the same composition.

Harvesting and sustainability

Chaga is hardly ever cultivated in its sclerotium form, so nearly all chaga on sale is wild-harvested. As demand has grown, several regions have reported increased pressure on forests. Careful foragers follow a few simple rules:

• harvest only from living birch trees, and only from well-developed growths;
• leave part of the chaga on the tree so it can regrow;
• avoid damaging the trunk beyond the harvest area;
• respect local foraging rules and get the landowner's permission.

There are also products made from cultivated chaga mycelium. Their composition differs from wild sclerotium, not least because they do not grow on birch. Our article on fruiting body vs mycelium explains why the part used changes the product.

How to make chaga tea

Chaga tea is the most traditional way to use it. A quick steep is not enough: chaga is very hard and releases its compounds slowly.

1. Choose the form: chunks, coarse granules or powder. Chunks can often be reused several times.
2. Simmer, do not boil hard: put the chaga in water and let it simmer for a long time, often an hour or more for chunks. Powder needs less time.
3. Strain: pour through a fine strainer or filter to remove particles.
4. Taste: the drink is dark brown, woody and earthy, slightly vanilla-like, with a hint of bitterness.

Chaga contains no caffeine. If you drink it, keep amounts moderate and read the precautions below.

Compounds under study

Chaga contains polysaccharides including beta-glucans, triterpenes such as inotodiol, betulin and betulinic acid, polyphenols, and melanin-like pigments that give it its colour. These substances are widely studied, mostly in preclinical research on cells or animals. Human studies remain scarce. This research does not allow any health effect to be attributed to chaga, and Swiss law does not permit such claims.

An important precaution: oxalates

Chaga is particularly rich in oxalates, compounds also found in spinach and rhubarb. In large amounts they can contribute to kidney stones. Cases of oxalate-related kidney damage have been described in people who consumed large quantities of chaga powder over a long period.

As a precaution, ask a doctor before using chaga if you have a history of kidney stones or kidney disease, take anticoagulants or diabetes medication, or are pregnant or breastfeeding. Avoid high doses over long periods.

Chaga and Swiss regulations

In Switzerland, chaga sold as tea or as a supplement falls under food law. Health claims are limited to an official list (annex 14 of the ordinance on food information), which contains nothing on chaga. A product promising to strengthen your defences, "detox" you or protect against disease is therefore not following the rules. The company selling it in Switzerland is responsible for its compliance. To spot a reliable product, see where to buy functional mushrooms in Switzerland.

Chaga or reishi?

Chaga and reishi are often mentioned together, since both grow on wood and are mostly used as extracts or teas. They still differ clearly in origin, taste and composition. We compare them in detail in reishi vs chaga: the differences, and reishi has its own complete guide.

Hymne and chaga

Hymne does not offer chaga. Our range brings together three liquid formulas: Morphée, with lion's mane; Vénus, with Polyporus and vegan collagen; and Hercule, with reishi and Agaricus blazei, currently almost out of stock. To see where chaga sits among other mushrooms, read our four-mushroom comparison.

Frequently asked questions

Does chaga grow in Switzerland?

It can occur on birch trees, but it is rare. Most chaga on sale comes from boreal forests in Russia, Scandinavia or Canada.

Can I harvest my own chaga?

Only with reliable identification, the landowner's permission and respect for local rules. Take only part of the growth and do not damage the tree.

How much chaga tea is safe to drink?

There is no official amount. Because of the oxalates, stay moderate, avoid heavy daily use over long periods and ask for advice if in doubt.

Does Hymne sell chaga?

No. Hymne offers lion's mane, reishi with Agaricus blazei, and Polyporus.

Prefer a ready-to-use functional mushroom with no tea to brew? Explore the Hymne range, in liquid form, formulated in Geneva and made in Switzerland.