Quaternary Ammonium Salts: (QUATS) Salt derivatives used in waterproof sunscreens because they impart cationic properties to compounds (reduce static electricity). QUATS chemically react with the skin, making lotions more water resistant.

Quaternium-15: Preservative used in cosmetics. Water soluble anti microbial agent that fights bacteria. A quaternary ammonium salt. See Quaternary Ammonium Salts.

Qnaternium-19: A preservative used in cosmetics than has anti-microbial benefits. A quaternary ammonium salt. See Quaternary Ammonium Salts.

Quercetin: Quercetin is a very highly concentrated form of Bioflavonoids derived from citrus fruit. See Bioflavonoids.

Quince Seed: A creamy, gummy plant-derived extract of the quince tree. Used in skin and hair care products as a treatment for dry, chapped hands or damaged hair.