Chaga

Chaga, Inonotus obliquus, is not shaped like a mushroom. It is a black, cracked mass that grows on living birch, rust-orange the whole way through. There is no chaga farm, and it is still wild-harvested by the lot. It is in our coffee for the flavour and the tradition.

What is chaga?

It looks like a burnt scab on the side of a tree. Black and cracked outside, the colour of charcoal, and when you break one open it is rust-orange the whole way in, like the inside of a cork.

The black chunk is a sclerotium, not a fruit. It is a dense survival mass the fungus builds inside a living birch, and it takes years to reach a size worth harvesting. We say sclerotium on the bag rather than fruiting body, because that is what it is. The fruiting-body rule we hold ourselves to is about the lion's mane, and about not selling you grain. Chaga has no mycelium-on-rice version to fake.

There is no chaga farm. Nobody has managed to make growing it on a living birch pay against the years it takes, so it is still gathered wild and bought by the lot. Every lot tastes a little different, which is one of the reasons a drop is 300 bags and not 30,000.

Where does chaga come from?

Siberia, mostly, and the birch forest that runs across the top of the northern hemisphere. In 1955 the Soviet Ministry of Health gave a chaga extract an official pharmacopoeia entry, under the name Befungin. Very few traditional fungi have ever had one.

Long before that, the Khanty people of western Siberia called it the gift of the forest. They ground it and boiled it, and it was the daily winter drink for centuries. Everything about how it is used today, ours included, is downstream of that.

What have researchers looked at?

The modern controlled human trial on chaga has not been run yet. Frost's 2023 survey in McIlvainea counted two human studies in the peer-reviewed literature, both more than thirty years old, and no controlled safety study on the record. When Vlassopoulou and colleagues gathered the human trials on fungal beta-glucans for Food and Function in 2021, no chaga trial met the bar to be included.

So this is an open field in the most literal sense. Centuries of documented daily use on one side, a laboratory record that is still mostly chemistry on the other, and nobody has yet done the work in the middle. For a research team that is an opportunity rather than a gap, and it is a fair bet somebody is writing the protocol now.

We put that here in plain sight because the alternative is borrowing another mushroom's trials and hoping the footnote goes unread. That is how this category earned its reputation, and we are not adding to it.

What is actually in chaga?

Chaga is where the purity question gets interesting, because the chemistry can tell real material from a grain product with a chaga label on it. Windsor and colleagues did exactly that in the International Journal of Molecular Sciences in 2025, testing authentic wildcrafted chaga against fermented grain products sold as chaga.

Beta-glucans are the beta-(1,3),(1,6)-D-glucans that build a fungal cell wall. Starch is alpha-glucan and comes from the grain. The phrase total polysaccharides is one number made of two, because it adds them together, which is precisely how grain starch passes as mushroom on a label. The assay that separates them is McCleary and Draga, Journal of AOAC International, 2016, and it reports total glucan and alpha-glucan as two figures.

Ask any brand for beta-glucan and alpha-glucan as two separate numbers, and watch what comes back.

Who should skip it

Chaga is high in oxalate. Anyone with a history of kidney stones, anyone pregnant or nursing, and anyone on blood thinners should skip it. Talk to your doctor before starting any supplement. This is on the bag and on the product page too, and it stays there.

Why it is in our bag

For the flavour, which is dark and faintly woody under the coffee, and for the tradition, which is the older half of the reason anybody drinks it at all. That is the whole answer and it is the same answer on the bag.

Lion's mane and chaga, in the bag · $34

Sources

Windsor et al., International Journal of Molecular Sciences, 2025 · McCleary and Draga, Journal of AOAC International, 2016 · Frost, McIlvainea, 2023 · Vlassopoulou et al., Food and Function, 2021 · Soviet pharmacopoeia, 1955 · Khanty traditional name. Found something we got wrong? Send us the study at hello@fruitingbody.io and the correction goes on this page with the date it changed.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.