Quercetin

Quercetin can stabilize mast cells and affect histamine-related release, so itchy nose, sneezing, and watery discharge in pollen season are often milder. For people who rub their nose as soon as windows open in spring, changes in how often they blow their nose and how clear the airway feels are more often noticeable after several weeks of continued use.

The same flavonol also maps onto cytokines and oxidative markers, so whole-body low-grade inflammation and morning joint tightness can be recorded together. For people who recover slowly after exercise or wake with stiff joints, differences in comfort and ease of movement are more often noticeable after several weeks of continued use.