Fisetin FAQ: Common Questions Answered

Fisetin has been consumed through foods for millennia. In clinical trials, doses of 20 mg/kg/day for 2 consecutive days have been used without serious adverse events. Mild GI symptoms are the most commonly reported side effects.

There is no established recommended dosage. Clinical trials have used approximately 20 mg/kg/day (roughly 1400 mg for a 70 kg adult) for 2 consecutive days in intermittent protocols.

No. Typical dietary intake is 0.2–1.4 mg/day. Research doses are 1000× higher (1400+ mg). You'd need to consume approximately 8 pounds of strawberries to match a single senolytic research dose.

In cell culture and animal studies, yes. Fisetin reduced senescent cell markers by 50–70% in the 2018 Mayo Clinic study. Human tissue clearance has not been demonstrated.

Both are flavonoid senolytics. Fisetin showed greater senolytic potency in the 2018 Mayo Clinic screening. Research suggests they may be synergistic when used together.

No. Fisetin is classified as a dietary supplement under DSHEA and has not been evaluated or approved by the FDA to diagnose, treat, cure, or prevent any disease.

In mice, fisetin extended lifespan by approximately 10%. No human lifespan studies have been conducted. Claims beyond published research are not supported by evidence.

The most common adverse events are mild gastrointestinal symptoms: nausea, loose stools, and abdominal discomfort. These typically resolve without intervention.

Clinical trials have used intermittent 'hit-and-run' protocols: 2 consecutive days of dosing, followed by 28 days off. Daily continuous dosing has not been rigorously studied.

Fisetin may interact with medications metabolized by CYP3A4 and CYP1A2 enzymes based on in vitro studies. Clinical drug interaction studies have not been published. Consult a healthcare provider.

Fisetin and urolithin A target different aging pathways (senolysis vs mitophagy). They may be complementary rather than competitive. Urolithin A has more published human RCTs.

No consumer-available test can measure whether fisetin supplementation is producing its intended biological effects. Anecdotal reports vary widely.

Fisetin's evidence grade is 'preclinical/early human'. The decision to supplement should be made in consultation with a healthcare provider, considering individual health status and goals.

The 2018 Yousefzadeh et al. study demonstrating senolytic activity and lifespan extension in mice is the most influential paper.

Key clinical trial results expected in 2026–2027 may significantly change the evidence landscape for fisetin.