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Fisetin

A plant flavonoid studied as a senolytic to clear aged cells.

Preliminary evidence ⏳Longevity

✚ Updated · How we grade evidence

Evidence tier
Preliminary
Research weight
Citations
8 verified / 8
Classification
Longevity
❝
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.

OutcomeEvidenceEffectStudies
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. Preliminary ↑ benefit 2
Knee osteoarthritis pain / inflammationPhase I/II RCT (n=74) was well tolerated but showed no clear improvement in WOMAC pain. Preliminary — no effect · negligible 1
Senolysis / anti-aging (clear senescent cells)Lifespan extension and senolytic activity shown only in mice and human cells in vitro; no human efficacy demonstrated. No Evidence ↔ mixed 2
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.

Key Studies

Systematic review Kumar 2025 (nephrotoxicity) ✓ PubMed
Systematic review found fisetin protective against kidney injury/nephropathy in preclinical studies; clinical dosing and human evidence still lacking.
Systematic review Yamaura 2022 (bone/cartilage) ✓ PubMed
Systematic review: fisetin shows pro-bone and chondroprotective effects in preclinical models, but human osteoporosis/OA efficacy remains unproven.
RCT OARSI 2025 (knee OA RCT) ✓ Source
Phase I/II RCT, 74 adults, fisetin 100 mg/day x2 days intermittently: well tolerated (safety primary endpoint) but no clear improvement in WOMAC pain.
RCT Verdoorn 2021 ✓ PubMed
Design/rationale for COVID-FIS senolytic trials; oral fisetin 20 mg/kg/day x2 days tested in older skilled-nursing residents with no serious safety signals.
RCT Wong 2022 (bioavailability RCT) ✓ Full text
Randomised crossover in healthy adults: a hybrid-hydrogel formulation raised fisetin plasma exposure vs standard fisetin, underscoring poor native oral bioavailability.
Review Theodosiou 2025 (reproductive health) ✓ Full text
Review: fisetin modulates ovarian aging and fibrosis in vitro/animal models; direct human reproductive-health evidence is absent.
Review Yousefzadeh 2018 ✓ PubMed
Fisetin was the most potent of 10 flavonoid senolytics; intermittent dosing late in life extended median and maximum lifespan in aged mice.
Review Zhu 2017 ✓ PubMed
Fisetin selectively induced apoptosis in senescent (not proliferating) human endothelial cells, establishing flavonoid senolytic activity in human cells.
8 sources cited · 8 verified Search all studies on PubMed ↗

Common questions about Fisetin

What is Fisetin used for?

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 8 sources for Fisetin, graded "Preliminary".

Cite this page
APA

Peh, D. (2026). Fisetin: Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 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 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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