Buserelin is a medication which is used primarily in the treatment of prostate cancer and endometriosis.It is also used for other indications such as the treatment of premenopausal breast cancer, uterine fibroids, and early puberty, in assisted reproduction for female infertility, and as a part of transgender hormone therapy. In addition, buserelin is used in veterinary medicine. The medication is typically used as a nasal spray three times per day, but is also available for use as a solution or implant for injection into fat.