Polyquaternium (PQ) is a water-soluble polymer used extensively in personal care products, particularly in hair care and skin care. PQ is known for its excellent conditioning properties, making it an ideal ingredient for shampoos, conditioners, and leave-in treatments. It works by forming a protective film on the surface of the hair or skin, providing moisture retention, smoothness, and a silky feel. In skin care, PQ is used in lotions and creams to improve the skin's texture and prevent dryness. It also enhances the performance of other active ingredients, allowing for better efficacy in personal care formulations.