¶ Fisetin
| Label | Value |
|---|---|
| Chemical Name | 3,3',4',7-tetrahydroxyflavone |
| Formula | C15H10O6 |
| Class | Flavonol (polyphenol) |
| Natural Sources | Strawberries, apples, persimmons, onions[1] |
| Primary Actions | Senolytic (cell-type specific), anti-inflammatory, antioxidant |
| Human Evidence | Early / limited |
| Oral Bioavailability | Low (improved by specialty formulations) |
| Investigational Dose | 20 mg/kg/day x 2 days (trial protocol)[2][3] |
Purpose of this page: quick, practical guidance first, then the deeper evidence and mechanisms.
Key facts (60‑second read):
- What it is: a plant flavonol studied for senescent‑cell clearance and inflammation reduction.
- What it might do: reduce senescence markers and improve physical function in animals; human outcomes not proven.[4]
- Evidence maturity: strong preclinical, early human safety/PK, clinical outcomes pending.[5][2:1]
- Food vs supplement: food provides microgram‑level intake; research uses hundreds to thousands of mg.[1:1]
At a glance Q/A
- Does it extend lifespan in humans? No human lifespan data yet; evidence is preclinical.
- Most plausible near‑term outcomes: biomarkers and physical function signals (hypothesized; unproven).
- Who should avoid it? Pregnancy/breastfeeding, children, or anyone told to avoid investigational supplements.[2:2]
BOTTOM LINE
Fisetin is one of the most promising natural senolytics in preclinical research, but human longevity benefits remain unproven. Treat it as investigational, not established anti‑aging therapy.
¶ Safety Traffic Light
| Green (most healthy adults) | Yellow (use caution) | Red (avoid) |
|---|---|---|
| Short‑term use appears well tolerated in a small PK study.[5:1] | Medications sensitive to CYP2C8 inhibition or with tight therapeutic windows.[6] | Pregnancy/breastfeeding, children, or anyone advised to avoid investigational supplements.[2:3] |
¶ Why People Care About Fisetin
Aging tissues accumulate senescent cells that stop dividing but remain metabolically active. These cells secrete inflammatory factors called the senescence‑associated secretory phenotype (SASP), which can disrupt tissue function and drive chronic disease.[4:1] Senolytics are agents that selectively remove senescent cells. Fisetin has emerged as a leading natural senolytic candidate because it:[4:2][7]
- Eliminates certain types of senescent cells in vitro and in animal models
- Reduces senescence markers in aged tissues
- Improves healthspan and lifespan in mouse studies[4:3]
¶ Reality Check: What We Know vs. What We Don’t
¶ What looks strong
- Multiple animal studies show reduced senescence markers and improved physical function.[4:4]
- The flagship mouse study reported lifespan extension and health improvements with late‑life dosing.[4:5]
¶ What is still uncertain
- No large‑scale human trials have demonstrated lifespan or major clinical outcomes.
- Senolytic effects are cell‑type specific and may not generalize across tissues.[4:6][7:1]
- Bioavailability is poor in standard formulations, which may limit real‑world effectiveness.[5:2]
¶ Evidence Summary
| Outcome | Effect | Evidence Level | Consistency |
|---|---|---|---|
| Senescent Cell Clearance | High (Animal / Tissue) | High | |
| Inflammation Reduction | Moderate (Animal) | Moderate | |
| Physical Function (Frailty) | Moderate (Animal) | Moderate | |
| Cognitive Effects | Low‑Moderate (Animal) | Mixed | |
| Human Safety / PK | Early (Small trials) | Limited |
¶ Human Evidence & Clinical Trials
¶ Active or Recent Trials
- NCT06431932: Phase 1 / pilot Phase 2a trial in healthy volunteers and older patients with multimorbidity. Intermittent dosing (20 mg/kg/day x 2 days) with PK, safety, and biomarker endpoints. Status: not yet recruiting as of last registry update.[2:4]
- NCT04733534: Open‑label trial in adult survivors of childhood cancer testing fisetin (20 mg/kg/day on days 1, 2, 30, 31) versus dasatinib + quercetin for frailty and senescence markers.[3:1]
- NCT05758246 (STOP‑Sepsis): Phase 2 trial testing fisetin in elderly patients with sepsis to assess clinical deterioration and senescent immune cell markers.[8]
¶ What to take from this
Human research is progressing, but most evidence is still about safety and biomarkers rather than clear clinical outcomes.[2:5][3:2][8:1]
¶ Food Sources vs. Supplement Doses
Fisetin exists naturally in foods, especially strawberries, but dietary amounts are tiny relative to research doses.
| Food | Approx. Fisetin (ug/g fresh weight)[1:2] |
|---|---|
| Strawberry | ~160 |
| Apple | ~26.9 |
| Persimmon | ~10.5 |
| Onion | ~4.8 |
So what? At ~160 ug/g, a 100 g serving of strawberries provides ~16 mg of fisetin, far below research protocols that use gram‑level doses.[1:3]
¶ Practical Use (If You Choose to Experiment)
¶ Protocol Card
| Label | Value |
|---|---|
| Typical Research Strategy | Intermittent "hit‑and‑run" dosing, not daily long‑term use |
| Common Investigational Dose | 20 mg/kg/day for 2 consecutive days (clinical trial protocols)[2:6][3:3] |
| Route | Oral |
| Timing | Often taken with food/fat to improve absorption |
| Cycling | Monthly or periodic cycles in research protocols (not standardized) |
NOT MEDICAL ADVICE
If you choose to use fisetin, consider it experimental and discuss with a clinician, especially if you take medications.
Pragmatic best practices:
- Favor intermittent dosing over continuous daily use
- Take with food/fat to improve absorption
- Track simple outcomes (energy, recovery, inflammation markers if available)
Transition: If you decide to use fisetin, it helps to understand how it compares with other senolytics and lifestyle‑aligned alternatives.
Deep Dive: Mechanistic Details
Mechanisms of Action
Senolytic Activity
SASP Suppression & Inflammation Control
By reducing senescent cell burden and modulating inflammatory signaling, fisetin can lower SASP‑associated cytokine activity in preclinical models.[4:8]
Antioxidant & Nrf2 Pathway Activation
Fisetin can activate endogenous antioxidant defenses (e.g., Nrf2 signaling) and reduce oxidative stress, which may indirectly reduce senescence burden.[5:3]
Pharmacokinetics & Bioavailability
Fisetin has poor water solubility and low oral bioavailability. A 2022 human crossover study tested a specialty hybrid‑hydrogel formulation (FF‑20) versus unformulated fisetin:[5:4]
- Dose: 1000 mg FF‑20 (delivering 192 mg fisetin) vs 1000 mg unformulated fisetin
- Result: 26.9x higher AUC and 23x higher Cmax with the FF‑20 formulation
- Safety: No adverse events reported in the small study
This suggests that formulation matters as much as dose.
Safety, Side Effects, and Interactions
¶ General Safety
Human safety data are limited but short‑term trials report good tolerability. Long‑term effects are unknown.[5:5][2:7]
¶ Drug Interactions (CYP Enzymes)
In vitro data suggest fisetin and its metabolite geraldol can inhibit CYP2C8, which may affect drugs metabolized by this enzyme. Use caution with narrow‑therapeutic‑index medications.[6:1]
¶ Trial Exclusions (Practical Red Flags)
Ongoing clinical trials commonly exclude people who are pregnant/breastfeeding or have unstable chronic disease, and may exclude some CYP‑interacting medications. If a trial excludes you, that is a strong signal to avoid self‑experimentation.[2:8]
¶ Compare With
Fisetin sits in a broader senolytic and longevity ecosystem. Comparisons help clarify whether you want a senolytic effect, a mitochondrial effect, or a more lifestyle‑aligned intervention.
- Quercetin + Dasatinib (D+Q): synthetic + natural senolytic combination with early human data in specific diseases
- Navitoclax (ABT‑263): potent senolytic with known toxicity risks
- Spermidine, Urolithin A: more lifestyle‑aligned interventions with broader human data but different mechanisms
¶ Appendix
¶ Frequently Asked Questions
Is fisetin proven to extend human lifespan?
No. The strongest evidence for lifespan extension comes from mouse studies. Human trials are still ongoing.
Can I get a senolytic dose from food?
Not realistically. Dietary fisetin is measured in micrograms per gram, while research doses are in hundreds to thousands of milligrams.
Why do people cycle fisetin instead of taking it daily?
Senolytics are thought to work via a "hit‑and‑run" effect: remove senescent cells, then stop until they accumulate again. This is a hypothesis supported by preclinical models, not settled clinical guidance.
¶ References
Fisetin content in foods. Review citing strawberries (~160 ug/g) and other sources. https://pmc.ncbi.nlm.nih.gov/articles/PMC9961076/ ↩︎ ↩︎ ↩︎ ↩︎
Fisetin in multimorbidity clinical trial registry (NCT06431932). https://ichgcp.net/clinical-trials-registry/NCT06431932 ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
NCT04733534. Open‑label trial of senolytics including fisetin in adult survivors of childhood cancer. https://clinicaltrials.gov/study/NCT04733534 ↩︎ ↩︎ ↩︎ ↩︎
Yousefzadeh MJ, et al. Fisetin is a senotherapeutic that extends health and lifespan. EBioMedicine. 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC6197652/ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Krishnakumar IM, et al. Enhanced bioavailability and pharmacokinetics of a hybrid‑hydrogel formulation of fisetin in healthy individuals. J Nutr Sci. 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC9574875/ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Selective inhibition of CYP2C8 by fisetin and geraldol (in vitro). https://pubmed.ncbi.nlm.nih.gov/29454704/ ↩︎ ↩︎
Zhu Y, et al. New agents that target senescent cells: fisetin and BCL‑XL inhibitors. Aging (Albany NY). 2017. https://pmc.ncbi.nlm.nih.gov/articles/PMC5391241/ ↩︎ ↩︎ ↩︎
STOP‑Sepsis trial protocol (NCT05758246). https://pmc.ncbi.nlm.nih.gov/articles/PMC11492760/ ↩︎ ↩︎