What quercetin is, what the human evidence shows, why its 'senolytic' reputation comes mostly from lab and animal research, doses, drug interactions and absorption.
Quercetin is a plant flavonoid found in onions, apples, berries and tea. Its "senolytic" (senescent cell-clearing) reputation comes from cell and animal studies and from small human pilot studies that combined it with dasatinib, a prescription cancer drug; quercetin alone has not been shown to clear senescent cells or slow aging in people. Human trials at around 500 to 1,000 mg a day show small, inconsistent effects on markers like blood pressure and inflammation.
Quercetin is one of the most common flavonoids in the diet, found in onions (especially red onions), apples, berries, broccoli and tea. It has antioxidant and anti-inflammatory activity in lab studies. As a supplement, it is poorly absorbed, which is why some products use liposomal or other delivery forms; none of these has been shown to make a specific product work better in people.
Senescent cells are damaged cells that stop dividing and release inflammatory signals. In lab and animal studies, quercetin combined with dasatinib (D+Q) cleared some of these cells. Human studies of D+Q have been small pilot studies, and they used a prescription drug alongside quercetin. Quercetin on its own has not been shown to clear senescent cells in people.
Trials of quercetin at around 500 to 1,000 mg a day have reported small, inconsistent effects on blood pressure and markers of inflammation. That is a long way from evidence that it improves health or longevity.
Quercetin may interact with drugs processed by liver enzymes or P-glycoprotein (such as cyclosporine and some statins and calcium-channel blockers), may reduce the effect of quinolone antibiotics such as ciprofloxacin, and may add to the effect of blood thinners. People with kidney disease should avoid high doses, and it hasn't been studied at supplement doses in pregnancy or breastfeeding.
GenuinePurity Liposomal Quercetin provides 250 mg per capsule, taken twice daily (500 mg a day), within the range used in human trials. No study has tested this product. GenuinePurity Longevity+ does not contain quercetin; it combines NMN, resveratrol, CoQ10, cycloastragenol and selenium.