Fisetin, found in strawberries, is one of the most-studied natural senolytics — compounds that selectively trigger apoptosis in senescent cells, the worn-out cells that stop dividing but linger and secrete inflammatory signals that accelerate aging in surrounding tissue. Mayo Clinic researchers have driven much of the senolytic research interest, with rodent studies showing extended healthspan and reduced age-related pathology. Unlike daily supplements, fisetin protocols in the biohacking community are typically pulsed — taken at a higher dose for two consecutive days per month rather than continuously — based on the theory that senescent cells only need periodic clearance, not constant suppression.