What it means
Fisetin is a flavonol found in strawberries, apples, persimmons and onions, in small amounts. In 2018 a screen of natural compounds at the Mayo Clinic identified it as the most potent senolytic among them in cultured cells, and the follow-up in mice made it a longevity-supplement staple.
Supplements provide 100–500 mg per capsule; trial protocols use far more — around 20 mg per kg of body weight for two consecutive days, repeated monthly — on the "hit-and-run" senolytic model.
Why it matters for longevity
If a food-derived flavonoid could clear senescent cells in people, it would be the first accessible senolytic. That is why fisetin has more registered human trials than any other senolytic candidate, including trials in frailty, osteoarthritis, kidney function and post-COVID recovery.
What the evidence says
Yousefzadeh 2018 (EBioMedicine): fisetin reduced senescent-cell markers in aged mice and extended median lifespan by about 10% when started late in life. It also lowered inflammatory markers and improved tissue function in several mouse models.
Human data: a 2023 trial in osteoarthritis (fisetin 20 mg/kg, two days) found reduced inflammatory markers but no significant functional benefit; the Mayo AFFIRM-LITE frailty trial has not published its main results. Oral bioavailability is poor — most fisetin is metabolised before it reaches tissue — and no trial has yet shown reduced senescent-cell burden in human tissue after oral fisetin.
How to measure or use it
- Senescent-cell burden cannot be tracked from a routine blood test; trials use tissue biopsies and SASP cytokine panels. hs-CRP and IL-6 are the accessible proxies.
- Supplement doses (100–500 mg) are far below the trial doses; the trial doses are not evidenced for self-use.
- The evidenced routes to lower senescent burden remain exercise, body-fat reduction and sleep.
Related
- Supplements that have evidence — the ranking, with fisetin graded
- Inflammation and immunity — what the SASP does
- The longevity drugs — senolytics in context
Frequently asked questions
Does fisetin work in humans?
Not yet shown. Mouse data are positive; the completed human trials are small and have not demonstrated senolytic effects or clear functional benefit.
What dose is used in trials?
About 20 mg per kg of body weight on two consecutive days, repeated monthly. Supplement capsules are a fraction of that.
Is it the same as quercetin?
Related flavonols with overlapping actions. Quercetin's senolytic evidence is as part of the dasatinib combination; fisetin was tested alone.
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