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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.

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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.

How to take it

TimingThe tested protocol is 2-3 consecutive days once a month, not daily — everyday label doses match no studied schedule.
With food?With a meal containing fat, since fisetin is fat-soluble and poorly absorbed otherwise.
Worth knowingDo not run a senolytic protocol during active cancer therapy without oncologist input — senescent cells also have roles in wound healing and tumour suppression.

Interactions

With medications

  • warfarin, DOACs and antiplatelet drugs

    Fisetin has antiplatelet activity, which matters especially at the gram-level doses used in senolytic protocols. do not combine without medical supervision

  • drugs metabolised by CYP2C9 or CYP3A4, including narrow-therapeutic-index drugs

    Fisetin inhibits both enzymes and can raise their blood levels. talk to your doctor before combining

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does fisetin extend lifespan?

No reliable evidence: the NIA Interventions Testing Program reported in 2024 that fisetin did not significantly affect lifespan in mice of either sex. The 2018 mouse result behind fisetin's popularity has not replicated under rigorous conditions.

Is fisetin a proven senolytic in humans?

No — fisetin's senolytic effect has been shown only in mice and in human fat tissue outside the body. Several small human trials of fisetin have been registered or completed, but none has published a convincing clinical benefit, so the evidence is limited.

How is fisetin dosed in senolytic protocols?

Human fisetin trials use an intermittent protocol: 20 mg/kg/day for 2-3 consecutive days, repeated monthly (roughly 1,000-1,600 mg/day for an adult), with a fat-containing meal. Daily label doses of 100-500 mg match no tested fisetin protocol.

Is fisetin safe with blood thinners?

Fisetin has antiplatelet activity and inhibits CYP2C9 and CYP3A4, so do not combine it with warfarin, DOACs or antiplatelet drugs without medical supervision, especially at gram-level doses. Long-term human safety of fisetin is unknown.

Scientific references

Where to buy

Double Wood Supplements, Fisetin, 100 mg, 60 Capsules

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