Birch Polypore (Fomitopsis betulina)
A bracket fungus common on birches in Poland, known for its discovery alongside Ötzi's remains — historically fascinating, but still not clinically confirmed as a supplement.
Table of contents
TL;DR
A bracket fungus common on birches in Poland, known for its discovery alongside Ötzi's remains — historically fascinating, but still not clinically confirmed as a supplement.
- →In vitro studies suggest antibacterial and antiparasitic activity of extracts
- →Preliminary laboratory studies point to potential anti-cancer activity of select compounds
- →Contains compounds with documented in vitro anti-inflammatory activity
| Latin name | Fomitopsis betulina (formerly Piptoporus betulinus) |
|---|---|
| Family | Fomitopsidaceae |
| Active substances | Agaric acid, betulin, betulinic acid, lupeol, piptamine |
| Form | Traditionally: dried fruiting-body slices for brewing; no standardized commercial extract |
| Level of evidence | Hypothesis — in vitro only, no clinical studies in humans |
| Interactions | Unknown — no studied interactions with drugs in humans |
| Status | Common in Poland; does not exist as a dietary supplement |
Understand
Overview
The birch polypore (Fomitopsis betulina, classified until 2016 as Piptoporus betulinus) is a common bracket fungus that parasitizes almost exclusively birch trees. It is very widespread in Poland. The mushroom gained international attention thanks to the 1991 discovery of Ötzi — a roughly 5,300-year-old mummy found in the Alps. Two pieces of fruiting body threaded on a leather strap were found with the body, interpreted as a deliberately carried kit, likely because of its content of agaric acid, which is toxic to whipworm (an intestinal parasite whose eggs were detected in Ötzi's intestines).
Historically the mushroom was also used as tinder and as a material for sharpening blades. Modern laboratory research confirms the presence of compounds with real biological activity, but there are no clinical studies in humans, nor an established supplement market.
Who might actually find this useful, and who wouldn't? At this early a research stage — in vitro only, zero human studies — it's hard to point to any group with proven health benefits from birch polypore today. The entry may instead interest people fascinated by ethnobotany, the history of medicine, and archaeology (the Ötzi angle), as well as mushroom foragers wanting to learn about this species from a scientific perspective. Given its bitter taste and the complete lack of safety data, there's no reason to treat it as something to consume regularly.
Where it's found
The birch polypore grows almost exclusively on birches, parasitizing the wood and causing brown rot. It is common throughout Poland and across the entire temperate zone of the Northern Hemisphere.
History of use
The oldest documented evidence of use dates back roughly 5,300 years — to Ötzi, who carried two pieces of fruiting body threaded on a leather strap, most likely because of agaric acid's action against intestinal parasites. In various European cultures the fruiting body was also used as natural tinder and as a strop for sharpening knives.
Mechanism of action
Fruiting bodies contain triterpenes (agaric acid, betulin and betulinic acid, lupeol) with documented in vitro biological activity. In laboratory studies, extracts and isolated compounds showed antibacterial, antiparasitic, anti-inflammatory, and cytotoxic activity against selected cancer cell lines.
At the molecular level, betulinic acid triggers the mitochondrial apoptosis pathway — it destabilizes the mitochondrial membrane of cancer cells, leading to the release of cytochrome c and activation of caspase-9, followed by caspase-3. Agaric acid is a classic inhibitor, well known from bioenergetic biochemistry, of the mitochondrial adenine nucleotide carrier (ADP/ATP translocase) — this is the likely mechanism behind its antiparasitic activity. Piptamine, a compound with documented antibacterial activity, has also been isolated from the fruiting body.
Release of triterpenes from the fruiting body
Agaric acid, betulin, betulinic acid, and lupeol extracted from fungal tissue under laboratory conditions.
Disruption of mitochondrial energy production
Agaric acid inhibits the ADP/ATP translocase — a theoretical mechanism behind its antiparasitic activity.
Activation of the mitochondrial apoptosis pathway
Betulinic acid leads to cytochrome c release and a caspase cascade in cancer cells in vitro.
Antibacterial activity of piptamine
Inhibition of the growth of selected bacterial strains under laboratory conditions.
Evidence: limited — based on 2 studies in this database.
Benefits
Common myths
MythSince Ötzi carried this mushroom with him, it's scientifically proven that it treated intestinal parasites.
FactThis is a credible archaeological hypothesis, but it remains an interpretation, not a proven medical fact.
Forms & variants
Birch Polypore (Fomitopsis betulina) comes in several forms that differ in bioavailability and use case — the form you pick genuinely matters for how effective the supplementation is.
Dried fruiting body (slices)
The most common traditional form of use — sliced and dried for brewing.
Best for: Traditional decoction/herbal tea
Practice
Frequently asked questions
This isn't known for certain. It's strong circumstantial evidence (agaric acid plus parasite eggs found in his intestines), but not proof.
Dosage & timing
Typical dose
No standardized, safe dose has been established — it is not sold as a typical dietary supplement
Form
Traditionally: dried fruiting-body slices for brewing as a decoction
This information is educational and historical, not a dosing recommendation.
Best times to take it
- No established regimen
Safety
Side effects & contraindications
Possible side effects
No clinical studies assessing safety of consumption in humans
The fruiting body has a very bitter taste — in larger amounts it may cause gastrointestinal discomfort
Contraindications
Pregnancy and breastfeeding
Children — no data
Known mushroom allergy
Interactions
No documented drug-interaction studies in humans
Is it worth taking?
Who it's for
- In vitro studies suggest antibacterial and antiparasitic activity of extracts
- Preliminary laboratory studies point to potential anti-cancer activity of select compounds
- Contains compounds with documented in vitro anti-inflammatory activity
Not for
- Pregnancy and breastfeeding
- Children — no data
- Known mushroom allergy
Evidence
Worth knowing
The roughly 5,300-year-old fruiting body found with Ötzi is one of the oldest known examples of humans using mushrooms.
The fruiting body's springy tissue was traditionally used to sharpen razors and knives.
Studies
An ethanolic extract of birch polypore limited melanoma cell proliferation and viability in a dose-dependent manner in vitro, while maintaining relatively low cytotoxicity toward normal fibroblasts.
Bożek J, et al., International Journal of Molecular Sciences, 2022
Fomitopsis betulina (formerly Piptoporus betulinus): the Iceman's polypore fungus with modern biotechnological potential
Early-stage evidencePleszczyńska M, Lemieszek MK, Siwulski M, Wiater A, Rzeski W, Szczodrak J · World Journal of Microbiology and Biotechnology · 2017
A literature review describing historical and modern laboratory research — documented in vitro antibacterial, antiparasitic, anti-inflammatory, and anti-cancer activity, with no clinical studies.
View studyEffects of Piptoporus betulinus Ethanolic Extract on the Proliferation and Viability of Melanoma Cells
Research hypothesisBożek J, et al. · International Journal of Molecular Sciences · 2022
The extract dose-dependently limited melanoma cell proliferation and viability in vitro, with relatively low cytotoxicity toward normal fibroblasts.
View studySources & bibliography
Citations are illustrative for this demo version and require full bibliographic verification by the editorial team before production publication.
Compare with similar entries
About the authors of this entry
Author
Michał NowakClinical Dietitian
Michał specializes in metabolic nutrition, intermittent fasting and sports supplementation.
61 publications on this site
Medical review
dr Piotr ZielińskiEndocrinologist
Piotr reviews content on hormones, metabolic health and supplement pharmacology.
131 publications on this site
Related entries
4.0Siberian Chaga (Inonotus obliquus)
A black, corky growth that parasitizes birch trees, traditionally brewed as a tea in Siberia and Scandinavia — rich in antioxidant compounds, but with practically no clinical studies in humans.
4.2Tinder Fungus (Fomes fomentarius)
A legendary bracket fungus and Ötzi's companion — for millennia the primary raw material for fire-starting in Europe, today mostly a historical and ethnobotanical topic rather than a dietary supplement.
4.5Turkey Tail
The mushroom behind PSK and PSP — the only fungal polysaccharides registered in Japan as drugs supporting chemotherapy. Among the most solid clinical evidence of any functional mushroom, but this is NOT a standalone cancer therapy.
4.4Lion's Mane
A functional mushroom studied for its effect on nerve growth factor (NGF) and cognitive function — human evidence is still preliminary.
4.3Shiitake
A culinary-functional mushroom rich in lentinan and beta-glucans, studied clinically for immune modulation and lipid profile — one of the best-researched functional mushrooms on the market.
4.3Tremella (Snow Fungus)
A jelly-like mushroom trendy in cosmetics as a 'vegan alternative to hyaluronic acid' — real clinical trials in humans, however, mostly involve oral supplementation and endpoints other than skin hydration.
4.3Antrodia camphorata (Niu Chang Zhi)
A mushroom endemic to Taiwan, growing exclusively on an endangered camphor tree, traditionally used for the liver — one of the few RCTs in humans shows a promising, if modest, improvement in liver enzymes.
Comments (2)
- KW
Kasia W. 2 weeks ago
Very clearly explained, especially the interactions section — I hadn't seen it laid out this well anywhere else.
- MT
Marek T. a month ago
Are you planning to update this with the newest study from this year? I saw an interesting meta-analysis.