What the evidence says. Graded preliminary: fisetin is the most potent senolytic flavonoid in cell and mouse studies (extending lifespan in aged mice), but human trials so far are tiny, short (often a 2-day 'hit-and-run' dose), focused mainly on safety, and have not yet shown a convincing clinical benefit. Oral bioavailability is also poor. (Preliminary evidence: Early or small human trials; promising but not yet conclusive.)
What is Fisetin?
Fisetin is a longevity supplement used for clear senescent ('zombie') cells. NutriDex grades the human evidence as Preliminary. Fisetin is a flavonoid found in strawberries, apples and onions that has become a flagship 'senolytic' candidate — a compound meant to selectively kill senescent (worn-out) cells thought to drive aging. In aged mice, intermittent fisetin reduced senescence markers and extended median and maximum lifespan, making it the standout among ten flavonoids screened. Human evidence is far earlier. Mayo Clinic-led trials (AFFIRM, COVID-FIS) and a 74-person knee-osteoarthritis trial have mostly tested safety using a 2-day pulsed dose, and report no serious adverse events but no clearly proven efficacy yet; osteoarthritis pain and inflammation outcomes were not convincingly improved. Fisetin is also poorly absorbed orally and rapidly metabolised, so blood levels are very low. It is a promising, biologically plausible longevity tool — but as of 2026 the human data are preliminary, not proof that it slows aging or treats disease.
Purported Benefits
✓Clear senescent ('zombie') cells
✓Lower inflammation markers
✓Researched for frailty & aging
✓Antioxidant activity
Evidence by outcome
The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.
Outcome
Evidence
Effect
Studies
Safety / tolerability of pulsed dosingEarly human trials (COVID-FIS, knee OA) report no serious adverse events at 2-day pulsed doses; safety, not efficacy, was the endpoint.
Oral bioavailabilityCrossover RCT confirms native fisetin is poorly absorbed; plasma levels very low without special formulation.
Preliminary
⚠ risk
1
Dosing & Compounds
Typical Dose
Trial doses are 20 mg/kg/day (roughly 1,000–1,500 mg) for 2 consecutive days, given intermittently; everyday supplement doses of 100–500 mg/day are unstudied for longevity.
Active Compounds
Fisetin (3,3',4',7-tetrahydroxyflavone)
Safety & Cautions
⚠
Across early human trials (2-day pulsed dosing) fisetin has been well tolerated with no serious adverse events reported, though sample sizes are small and long-term daily safety is unstudied. As a flavonoid it can inhibit cytochrome-P450 and drug-transporter pathways, so it may theoretically raise levels of drugs metabolised by CYP3A4/CYP2C; caution with anticoagulants (added antiplatelet effect), antidiabetics (possible additive glucose lowering) and chemotherapy. Avoid in pregnancy and breastfeeding (no data), and tell your clinician before use if you take prescription medicines. Educational only — always check with your doctor or pharmacist before combining Fisetin with any medicine.
Fisetin is most often taken for Clear senescent ('zombie') cells, Lower inflammation markers, Researched for frailty & aging, Antioxidant activity. A plant flavonoid studied as a senolytic to clear aged cells.
Does Fisetin work — what does the evidence say?
Preliminary evidence. Early or small human trials; promising but not yet conclusive. Fisetin is a flavonoid found in strawberries, apples and onions that has become a flagship 'senolytic' candidate — a compound meant to selectively kill senescent (worn-out) cells thought to drive aging. In aged mice, intermittent fisetin reduced senescence markers and extended median and maximum lifespan, making it the standout among ten flavonoids screened. Human evidence is far earlier. Mayo Clinic-led trials (AFFIRM, COVID-FIS) and a 74-person knee-osteoarthritis trial have mostly tested safety using a 2-day pulsed dose, and report no serious adverse events but no clearly proven efficacy yet; osteoarthritis pain and inflammation outcomes were not convincingly improved. Fisetin is also poorly absorbed orally and rapidly metabolised, so blood levels are very low. It is a promising, biologically plausible longevity tool — but as of 2026 the human data are preliminary, not proof that it slows aging or treats disease.
What is the typical dose of Fisetin?
Trial doses are 20 mg/kg/day (roughly 1,000–1,500 mg) for 2 consecutive days, given intermittently; everyday supplement doses of 100–500 mg/day are unstudied for longevity.
Is Fisetin safe? Any cautions or side effects?
Across early human trials (2-day pulsed dosing) fisetin has been well tolerated with no serious adverse events reported, though sample sizes are small and long-term daily safety is unstudied. As a flavonoid it can inhibit cytochrome-P450 and drug-transporter pathways, so it may theoretically raise levels of drugs metabolised by CYP3A4/CYP2C; caution with anticoagulants (added antiplatelet effect), antidiabetics (possible additive glucose lowering) and chemotherapy. Avoid in pregnancy and breastfeeding (no data), and tell your clinician before use if you take prescription medicines.
How many studies support Fisetin?
NutriDex cites 10 sources for Fisetin, graded "Preliminary".
Cite this page
APA
Peh, D. (2026). Fisetin: Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 16 Sept 2026, from https://nutridex.info/s/fisetin
BibTeX
@misc{nutridex_fisetin,
author = {Peh, Daryl},
title = {Fisetin: Benefits, Dosage, Side Effects \& Evidence},
year = {2026},
howpublished = {NutriDex --- The Supplement Research Compendium},
url = {https://nutridex.info/s/fisetin},
note = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-09-16}
}
For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.