Relugolix is used in the treatment of advanced prostate cancer by reducing the production of testosterone, a hormone that can promote the growth of prostate cancer cells. It works by blocking the gonadotropin-releasing hormone (GnRH) receptor, which lowers levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), leading to decreased testosterone from the testes. This hormonal suppression helps slow tumor growth and manage disease progression. It is also used in combination with antiandrogens for more effective control of cancer symptoms. Additionally, relugolix is being studied for use in other hormone-sensitive conditions such as endometriosis and uterine fibroids in women, where modulation of sex hormones can reduce pain and abnormal bleeding. Its oral formulation offers a convenient alternative to injectable hormonal therapies.