Lower numbers = closer to natural. Higher numbers = more enhanced.
Why this rating?
Fisetin is a plant flavonol (found in strawberries, apples, onions) taken as a longevity/senolytic supplement. It does not build muscle, alter hormones, or enhance athletic performance. Its senolytic (senescent-cell-clearing) reputation rests largely on mouse data plus early human trials; as a strong antioxidant it may even blunt training adaptations if megadosed around workouts. Not WADA prohibited. Rated 1 as a dietary-supplement-tier antioxidant/senotherapeutic with no ergogenic effect.
Overview
A flavonol polyphenol best known as the leading candidate senolytic, a compound that selectively clears senescent ('zombie') cells that accumulate with age and secrete inflammatory signals. It is also a general antioxidant and anti-inflammatory. The distinctive practical feature is dosing: rather than daily use, senolytic protocols use short, high-dose pulses ('hit-and-run'), reflecting how senescent cells are cleared. Human evidence is early. Most of the strong data are still in mice.
Purpose & Use Cases
Senolytic / Senescent-Cell Clearance
The flagship use. In aged mice, fisetin reduced senescent-cell markers and extended health- and lifespan even when started late in life. Human trials (e.g. Mayo Clinic) are ongoing and preliminary.
Longevity / Anti-Inflammatory
By lowering senescent-cell burden and the associated inflammatory secretome, it is used as a general 'geroprotective' supplement.
Antioxidant
Scavenges free radicals: useful for general antioxidant goals, but see the training caveat (this same property can blunt adaptation if dosed around workouts).
Benefits
- Leading senolytic candidate (clears senescent cells in preclinical models)
- Extended health- and lifespan in aged mice
- Lowers senescence-associated inflammatory signalling (SASP)
- General antioxidant / anti-inflammatory activity
- Non-hormonal, inexpensive, well tolerated in short use
Good to Know
Human evidence is thin, mostly mouse data
The landmark result (Yousefzadeh et al. 2018) is in mice: fisetin cleared senescent cells and extended health- and lifespan even when started in old age. Human senolytic trials (Mayo Clinic) are early. They indicate the 2-day monthly regimen is well tolerated, but hard clinical outcomes are not yet established.
Why "hit-and-run" instead of daily
Senolytics work by triggering apoptosis in senescent cells that are already primed to die but resisting. You do not need constant exposure, a short high-dose pulse clears a fraction of them, then you stop for weeks. This is the opposite of how most supplements are dosed and is the key thing people get wrong.
Antioxidant vs. training tradeoff
Fisetin is a potent antioxidant. Exercise adaptation is partly driven by the very reactive oxygen species antioxidants mop up, so megadosing fisetin around workouts could blunt gains. The same nuance that applies to resveratrol and high-dose vitamin C/E. Dietary-level intake is not a concern.
Not performance-enhancing
Fisetin does not raise testosterone, build muscle, or improve strength/endurance. It sits firmly in the longevity/health bucket, relevant to a physique athlete only as a general-health add-on, not a PED.
Dosage Guidelines
| Experience Level | Dosage Range |
|---|---|
| Beginner | 100 – 500 mg/day |
| Intermediate | 1000 – 1500 mg/day |
| Advanced | 1500 – 2000 mg/day |
The 'hit-and-run' senolytic protocol used in Mayo Clinic-linked human trials (e.g. the knee-osteoarthritis RCT, NCT04210986) is 20 mg/kg/day on 2 consecutive days, repeated roughly monthly, about 1,400-2,000mg/day for a 70-100kg adult during those 2 days, then weeks off. Community 'hit-and-run' protocols mirror this, often quoted as 1,500-2,000mg/day crude fisetin (or 500-1,000mg/day for better-absorbed liposomal forms) for the 2 pulse days. The rationale: flood the system briefly to trigger senescent-cell apoptosis, then let the body recover. Fisetin is lipophilic and poorly absorbed (~10% bioavailability for crude powder), so take it with a fat-containing meal (some use liposomal forms for 3-5x better absorption). Lower daily doses (100-500mg) are used for general antioxidant goals but are not the senolytic strategy; the monthly pulse is typically maintained on an ongoing basis (cycle length above reflects a realistic commitment period, not a hard stop).
Oral bioavailability is poor and fisetin is rapidly conjugated and cleared, the basis for pulsed 'hit-and-run' dosing rather than daily use.
Side Effects
GI Upset
uncommonNausea or loose stools, mainly with the high senolytic pulse doses.
Take with a fatty meal; split the daily pulse into two servings.
Additive Bleeding Risk
rareLike many flavonoids/polyphenols, fisetin can have mild antiplatelet activity, which may add to bleeding risk alongside anticoagulants or other antiplatelet agents.
Caution with blood thinners, fish oil, or aspirin; pause before surgery.
General Mitigation Strategies
Well tolerated in the short human trials done so far. Take with fat for absorption and be mindful of additive bleeding risk. As with resveratrol, if muscle/endurance adaptation is the goal, do not megadose it right around training, time antioxidant use away from your key sessions.
Post Cycle Therapy (PCT)
Not hormonal. No PCT required.
How It Works
Fisetin acts as a senolytic: senescent cells survive by upregulating anti-apoptotic 'SCAP' pathways (notably PI3K/AKT and BCL-2 family survival signalling), and fisetin tips those cells back toward apoptosis while largely sparing healthy cells. Clearing the senescent-cell burden lowers the inflammatory secretome (SASP) they produce. Independently, fisetin is a direct antioxidant and activates Nrf2/sirtuin-related stress-response pathways. The antioxidant activity is a double-edged sword for lifters. The same free-radical scavenging that is 'anti-aging' can, if megadosed around training, blunt the exercise-induced signalling that drives adaptation (the same caveat as resveratrol).
Fundamentals
Reference on the practices relevant to Fisetin: how they are done and where they go wrong. Not a recommendation to use it.
Legal Status
Sold over the counter as a dietary supplement (USA).
Legal status varies by country and changes over time. This is a general summary, not legal advice.
WADA Status
Fisetin is a dietary flavonoid sold as a supplement and is not on the WADA Prohibited List.