Hydroxyethyl cellulose (HEC) is a water-soluble polymer derived from cellulose, commonly used as a thickening, emulsifying, and stabilizing agent in various industries, including cosmetics, pharmaceuticals, and food. It enhances the viscosity of solutions without altering their clarity and is also used in formulations for its ability to retain moisture. HEC is non-toxic and biodegradable, making it an environmentally friendly choice for many applications. Its versatility allows it to be used in products like shampoos, lotions, and paints.