L-Cystine dihydrochloride is widely used in the pharmaceutical industry as a supplement to support protein synthesis and promote tissue repair. It is often included in formulations aimed at improving skin, hair, and nail health due to its role in keratin production. In medical settings, it is utilized to treat conditions like cystinuria, where it helps reduce the formation of cystine stones in the kidneys. Additionally, it serves as a stabilizer in cell culture media, supporting the growth and maintenance of cells in laboratory research. Its antioxidant properties also make it valuable in combating oxidative stress in various therapeutic applications.