Agarikon (Fomitopsis officinalis)

One of the longest-lived fungi in the world — individual specimens can persist for over a century on old-growth conifers — and one of the oldest medicinal mushrooms on record, described by the Greek physician Dioscorides as "elixirium ad longam vitam" ("the elixir of long life") for treating consumption (what we now call tuberculosis).

Not medical advice. Not an antiviral treatment. Agarikon is also critically endangered — see Quality notes before considering any product claiming to contain it.

What the evidence shows

Laboratory (in-vitro) screening — including work associated with mycologist Paul Stamets in collaboration with NIAID and USAMRIID — has tested agarikon extracts against several high-priority pathogens (poxviruses, H5N1 influenza, and others), with some strains showing antiviral activity. This is early-stage, preclinical laboratory research only — there are no human clinical trials of agarikon for any infection.

Evidence level: preclinical; historical/traditional use is well documented, modern efficacy claims are not clinically proven.

How it's used

Historically, dried fruiting body prepared as a decoction or tincture. Modern availability is extremely limited (see below).

Safety

Documented modern human safety and dosing data are essentially absent, given how rare legitimate material is and how little modern human use exists. Treat any commercial "agarikon" product with scepticism about both authenticity and safety data. Not established as safe in pregnancy, breastfeeding, or alongside any medication.

Quality notes

Agarikon is classified as endangered by the IUCN (since 2019) — extinct in Ukraine, critically endangered across much of the Alps, and functionally extinct across large parts of its former North American range. It depends on undisturbed old-growth forest and is legally protected in most of its range, harvestable (if at all) only in tiny, regulated quantities. Any product marketed as containing significant wild agarikon should raise both an authenticity and a conservation-ethics concern.

Sources

Explore the other medicinal mushrooms or our full plant catalogue.