Relugolix is primarily used in the treatment of advanced prostate cancer. It works by reducing the production of testosterone, which can help slow the growth of prostate cancer cells. This medication is often prescribed for patients who require androgen deprivation therapy, a common approach in managing prostate cancer. Relugolix offers an oral alternative to other forms of hormone therapy, providing convenience and potentially fewer side effects for some patients. It is also being investigated for use in treating conditions like uterine fibroids and endometriosis, where hormone regulation is crucial for symptom management.