Quercetin

Quercetin is a bioflavinoid ingredient from plants. It occurs naturally in grapes (so it is also found in red wine), tea, onions, kale, tomatoes, berries, and many other fruits and vegetables, with the highest concentrations found in the leaves and skins. It functions as an antioxidant, skin-soothing agent, and restorative ingredient.

In terms of skin care, research has shown that a lipid-based (fat-based) delivery system is optimal for quercetin to exert antioxidant benefits. Even more exciting, this type of formula provides an initial burst of quercetin followed by sustained release over a 24-hour period. When quercetin is mixed with silicone and lipids, the intake is greater, as confirmed by testing on human skin. Emerging research also shows quercetin has protective effects against ultraviolet-B (UVB) radiation, though quercetin is not approved as an active sunscreen ingredient.

Higher amounts of quercetin impart a pale yellow to golden colour to cosmetics.