A plain guide to quercetin: what human trials show, why the senolytic label rests mostly on lab and animal work, typical doses, drug interactions and absorption.
Onions, apples, berries and tea contain quercetin, a plant flavonoid. The "senolytic" label, meaning it clears senescent cells, traces back to cell and animal studies and to small human pilot studies in which it was paired with dasatinib, a prescription cancer drug. Quercetin by itself hasn't been shown to clear senescent cells or slow aging in people. In human trials at around 500 to 1,000 mg a day, effects on markers such as blood pressure and inflammation were small and inconsistent.
Few flavonoids turn up in the diet as often as quercetin. Red onions in particular, along with apples, berries, broccoli and tea, supply it. Lab studies credit it with antioxidant and anti-inflammatory activity. Supplement forms are absorbed poorly, which explains why some products use liposomal or other delivery systems. Nothing shows that any of those makes a given product work better in people.
Senescent cells are damaged ones that no longer divide and that give off inflammatory signals. Lab and animal studies found that quercetin plus dasatinib (D+Q) cleared some of them. In people, D+Q has only been looked at in small pilot studies, and those involved a prescription drug along with the quercetin. Whether quercetin alone clears senescent cells in people hasn't been shown.
At roughly 500 to 1,000 mg a day, quercetin trials have reported small, inconsistent effects on blood pressure and inflammation markers. Those findings fall well short of showing that it improves health or longevity.
Some medicines are processed by liver enzymes or P-glycoprotein, including cyclosporine and certain statins and calcium-channel blockers, and quercetin may interact with them. It may also weaken quinolone antibiotics such as ciprofloxacin and strengthen the effect of blood thinners. High doses are best avoided by people with kidney disease. At supplement doses, it hasn't been studied in pregnancy or breastfeeding.
Each capsule of GenuinePurity Liposomal Quercetin holds 250 mg, and the directions call for two a day (500 mg a day), a dose inside the range used in human trials. No study has tested this product. GenuinePurity Longevity+ contains no quercetin; its formula is NMN, resveratrol, CoQ10, cycloastragenol and selenium.