Chaga and sleep: what research says and what really affects sleep

Short answer: no one has yet shown that chaga improves sleep. We did not find a study in the PubMed database that tracked sleep in people taking chaga, and according to a review, chaga research rests mainly on laboratory and animal experiments (Szychowski et al., 2021). More ordinary things have a documented effect on sleep: adults are advised to get 7 to 9 hours of sleep (Hirshkowitz et al., 2015), and caffeine disrupted sleep even when people took it 6 hours before going to bed (Drake et al., 2013). For long-term insomnia, European expert guidelines name cognitive behavioural therapy as the first step (Riemann et al., 2023). Chaga also contains a lot of oxalates, and cases of serious kidney damage after its long-term use have been described (Kikuchi et al., 2014).

Chaga, also known as the clinker polypore (Inonotus obliquus), is a fungus that grows as a parasite mainly on birch trees in the cold regions of the northern hemisphere. It does not look like a typical mushroom: on the trunk it forms a hard, black and cracked growth that is rusty brown inside. In Siberia and Finland, tea is traditionally brewed from it. Food supplements contain it as a dried powder or as an extract, for which manufacturers state the proportion of polysaccharides and beta-glucans.

Chaga extracts are studied mainly in test tubes and in mice. A review from 2021 summarises that in these experiments they acted as antioxidants and influenced immune cells, and their effect on blood sugar levels is also being studied. At the same time, the authors write that studies meeting the criteria of evidence-based medicine are missing (Szychowski et al., 2021). We did not find a controlled study of chaga in humans in the PubMed database in October 2026.

A result from a test tube or a mouse cannot be transferred to a person who takes a capsule in the morning. We do not know what dose would have any effect in humans, or how much of the studied substances the body absorbs from the mushroom. That is why we write about chaga as a mushroom with a long tradition and interesting laboratory research, not as a remedy for anything.

The link between chaga and sleep is a line of reasoning, not a measured result. It usually rests on the fact that chaga acts as an antioxidant in the laboratory, from which better recovery, and with it better sleep, is inferred. But chaga is not a sedative, it does not contain melatonin, and in the PubMed database we did not find a single study that measured falling asleep, sleep duration or sleep quality in people taking chaga. If someone promises you that you will sleep better after taking chaga, they have nothing to base it on.

The best supported things are the ones that sound the most ordinary. An expert panel of the American National Sleep Foundation recommends 7 to 9 hours of sleep for adults and 7 to 8 hours for older people (Hirshkowitz et al., 2015). In the study by Drake et al. (2013), 400 mg of caffeine disrupted sleep compared with placebo, whether people took it at bedtime, 3 hours or 6 hours before. The authors therefore recommend skipping a larger dose of caffeine at least 6 hours before bed. When people read from a glowing e-reader in the evening instead of a printed book, they took longer to fall asleep, produced less melatonin, their internal clock shifted and they were less alert in the morning (Chang et al., 2015).

A review of sleep hygiene research reports that regular bedtimes, exercise, noise, caffeine, nicotine, alcohol and daytime naps are related to sleep. But it honestly adds that the direct effect of individual tips on the sleep of the general population has so far been tested little, and that sleep hygiene education alone is not enough for real insomnia (Irish et al., 2015).

If you have been sleeping badly for several weeks or months, see a doctor rather than turning to food supplements. The European guidelines from 2023 name cognitive behavioural therapy for insomnia, in person or in digital form, as the first step for chronic insomnia in adults. Sleeping pills come next only when therapy is not enough, and according to the guidelines, herbal preparations (phytotherapeutics) are not suitable for insomnia (Riemann et al., 2023). Poor sleep can also be caused by another disorder, for example a breathing disorder during sleep, which an examination in a sleep laboratory will reveal.

Chaga contains a great deal of oxalates, substances from which the most common kidney stones form and which, at high intake, can be deposited directly in the kidneys. In Japan, doctors described a 72-year-old woman who took 4 to 5 teaspoons of chaga powder a day for half a year. Her kidneys failed to such an extent that she needed dialysis, and a biopsy found oxalate crystals (Kikuchi et al., 2014). A similar case was described in Korea: a 49-year-old man took chaga powder for several years and ended up with end-stage kidney failure. Doctors measured an extremely high oxalate content in the remaining mushroom and estimated that he had been taking in two to five times more oxalates a day than with a normal diet (Lee et al., 2020).

A substance isolated from chaga inhibited the clumping of blood platelets in the laboratory and in mice (Hyun et al., 2006), and animal experiments are investigating the effect of chaga on blood sugar levels (Szychowski et al., 2021). No one has verified this in humans, but caution is warranted. If you have kidney disease or a tendency to kidney stones, take blood thinners or diabetes medication, or are pregnant or breastfeeding, consult a doctor before taking chaga in any form. Reliable data for pregnancy and breastfeeding are lacking.

In collalloc MIND, chaga is one of four mushrooms, together with Lion’s Mane, Cordyceps and maitake. The daily dose of 4 capsules contains 600 mg of extract from each mushroom. The extract has at least 50% polysaccharides and at least 20% beta-glucans. MIND is caffeine-free and is taken in the morning; we do not recommend an evening dose. We do not offer it as a sleep aid and we do not promise that you will sleep better after taking it: MIND is a daily ritual, not a medicine or a nootropic. We describe what is in MIND and what research says about its mushrooms in the article collalloc MIND: what it contains and what research says, and why we do not consider mushrooms to be nootropics in the article What are nootropics, and are functional mushrooms among them?

The described cases of kidney damage involved people who took large amounts of chaga powder, for example 4 to 5 teaspoons a day, for months to years. Milligrams of extract and of dried mushroom cannot be compared directly, however, so the same applies to MIND: if you have kidney disease or take medication, consult a doctor.