Hydroxyethanesulfonic acid (HES), also known as isethionic acid, is a specialty chemical primarily used as an intermediate in the synthesis of mild surfactants such as sodium cocoyl isethionate, which are essential in personal care products like shampoos, soaps, and body washes for their gentle, non-irritating cleansing properties. In the textile industry, it serves as a dyeing auxiliary, improving the solubility, stability, and even distribution of dyes on fabrics. It also acts as a buffering agent in various industrial processes to maintain optimal pH levels. Additionally, HES is incorporated into hair and skin care formulations for its moisturizing and conditioning benefits. Its role as a versatile intermediate extends to the production of other specialty chemicals and additives.