Supplement analysis backed by scientific evidence · PT

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Limited evidenceLongevity & antioxidants

Fisetin

A senolytic flavonoid with a striking mouse result behind it — and a large, well-controlled replication attempt where fisetin failed to extend lifespan at all. Human trials are ongoing but none have reported a clinical benefit. This is a bet, not a treatment.

What the science says

  • Senolytic activity (clearing senescent cells) Limited evidence

    In the 2018 EBioMedicine paper that launched the field, fisetin reduced senescent cell markers in mouse tissue and extended median and maximum lifespan in aged mice even when started at 85% of median lifespan. The effect on human senescent cell burden has been shown only in ex vivo human adipose tissue, not in living people with a clinical endpoint.

  • Lifespan extension Limited evidence

    The NIA Interventions Testing Program — the gold standard for lifespan claims, run in genetically heterogeneous mice across three independent sites — tested fisetin and reported in 2024 that it did NOT significantly affect lifespan in either sex at the doses and schedules used. This is the single most important fact about fisetin and it is a negative one; the flattering 2018 result has not replicated under rigorous conditions.

  • Human clinical outcomes Limited evidence

    Several small human trials (frailty in older adults, osteoarthritis, post-COVID, chronic kidney disease) using intermittent high-dose fisetin have been registered or completed, but as of now none has published a convincing benefit on a clinically meaningful endpoint. Anyone selling fisetin on the strength of human evidence is ahead of the data.

  • Bioavailability Limited evidence

    Oral fisetin has very poor bioavailability (roughly 1-2% in rodents) with a half-life of a few hours, and plasma concentrations achieved from typical supplement doses are well below those that trigger senolysis in cell culture. Liposomal and phospholipid formulations improve absorption several-fold but have not been validated against a clinical outcome.

Dosage & safety

Studied doseHuman trials use an intermittent "hit and run" protocol modeled on the mouse work: 20 mg/kg/day for 2-3 consecutive days, repeated monthly (roughly 1,000-1,600 mg/day for an adult). Everyday supplement labels suggesting 100-500 mg daily do not match any tested protocol. Fisetin is fat-soluble — take with a meal. Dietary intake from strawberries, apples and onions is on the order of a few milligrams per day.
SafetyShort-term high-dose fisetin has been well tolerated in the small trials reported so far, with mild GI upset the main complaint, but long-term safety in humans is unknown. Fisetin inhibits CYP2C9 and CYP3A4 and has antiplatelet effects — a meaningful interaction risk with warfarin, DOACs, antiplatelets and narrow-therapeutic-index drugs, particularly at the gram-level doses used in senolytic protocols. Senescent cells have roles in wound healing and tumour suppression, so clearing them indiscriminately is not automatically desirable. Avoid in pregnancy, lactation, and in anyone on active cancer therapy without oncologist input.

Scientific references

Where to buy

Double Wood Supplements, Fisetin, 100 mg, 60 Capsules

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