Quercetin is the most abundant dietary flavonoid — found in onions, apples, berries, and green tea — and is emerging as a potential senolytic (kills senescent "zombie" cells). The Mayo Clinic's landmark senolytic protocol combines quercetin (1,000mg) + dasatinib to clear senescent cells in humans. Our research shows quercetin also has strong anti-allergy effects (mast cell stabilization), modest endurance performance improvement (2.9% in a meta-analysis), and significant antiviral activity (reduced COVID illness duration by 70% in one RCT). The main limitation is poor bioavailability (~2% without enhancement) — phytosomal and liposomal forms address this.
Quercetin works through multiple mechanisms: (1) mast cell stabilization — inhibits degranulation and histamine release (anti-allergy, superior to cromolyn sodium in vitro); (2) NF-κB inhibition — broad anti-inflammatory effect; (3) senolytic activity — selectively induces apoptosis in senescent cells by inhibiting pro-survival pathways (BCL-2 family, PI3K/Akt, HIF-1α) that zombie cells depend on; (4) antiviral — inhibits viral entry (3CLpro protease inhibitor for coronaviruses, neuraminidase inhibitor for influenza); (5) eNOS activation — increases NO for vasodilation (blood pressure reduction). The poor bioavailability (2%) is due to rapid phase II metabolism (glucuronidation/sulfation in liver and intestine). Phytosomal formulation wraps quercetin in phospholipid, increasing absorption 20x.
Reviewed by the Scan Dose Research Team and Clinical Advisory Board | Last updated:
Not medical advice. Based on published clinical research and systematic reviews.