Cysteamine hydrochloride is widely used in the treatment of cystinosis, a rare genetic disorder that causes the accumulation of cystine in cells. It works by reducing cystine levels through conversion to more water-soluble forms like cysteine, helping to prevent organ damage, particularly in the kidneys. Additionally, it is employed in the management of radiation sickness, where it acts as a radioprotective agent by reducing oxidative stress. In the field of dermatology, it is utilized in formulations for skin depigmentation, helping to treat conditions like melasma. It also finds applications in research as a reducing agent in biochemical studies and in the synthesis of various pharmaceutical compounds.