Fomes fomentarius

BotanicalBest with a meal

What is it

Fomes fomentarius, known as tinder fungus, amadou, or ice man's fungus (after its discovery on Otzi the Iceman), is a bracket fungus found on birch and beech trees. It is used in some traditional medicine systems and modern mushroom supplement blends.

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Immune support

Limited Evidence

Beta-glucan-mediated immune modulation is well-established for related mushrooms. Specific human evidence for F. fomentarius is limited.

How it works

F. fomentarius contains beta-glucans (especially branched 1,3/1,6 glucans), polysaccharide-protein complexes, triterpenes, and phenolic compounds. Like other medicinal mushrooms, the beta-glucan content is the primary basis for immune support claims. Preclinical studies suggest anti-inflammatory, immunomodulatory, and antitumor activity, but well-designed human clinical trials are limited.

Dosage

Typical mushroom extract doses range from 300 to 1000 mg/day. F. fomentarius lacks standardized clinical dosing.

When and how to take it

Take once or twice daily, typically with food.

1 commercial form

Compare the main delivery options and what they’re best suited for.

Fruiting body extract

Standardized to beta-glucan content in better products.

Beta-glucan absorption is partial.

Safety

Considered safe at typical doses. Mild GI upset is the most common report. Long-term safety data are limited.

Who should be cautious

Avoid in pregnancy and lactation due to limited safety data. Caution with immunosuppressant medications or in autoimmune conditions.

Interactions

Theoretical interactions with immunosuppressants and anticoagulants based on preclinical activity.

Frequently asked questions

Is Fomes fomentarius edible?⌄

It is too tough to eat directly. It is consumed as extract or tea after processing.

Why is it called ice man's fungus?⌄

Fomes fomentarius was found on Otzi, a 5,000-year-old mummified body discovered in the Alps, suggesting historical use as tinder and possibly medicine.

References

Fomes fomentarius on Wikidata — Wikidata link

Fomes fomentarius on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Fomes fomentarius (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.