Used primarily as a skin-lightening agent in cosmetic and dermatological products to treat hyperpigmentation, melasma, and age spots. It works by inhibiting tyrosinase, an enzyme involved in melanin production, thereby reducing dark discoloration. Commonly found in creams, serums, and lotions, it is available in over-the-counter and prescription strengths depending on concentration. Also employed as a reducing agent in photographic developing processes, where it helps convert exposed silver halides to metallic silver. In industrial applications, it acts as a polymerization inhibitor in monomers like acrylates and methacrylates during storage and transport, preventing premature curing. Additionally, hydroquinone is used in some hair dyes and as an antioxidant in rubber and plastics to improve stability and extend shelf life.