Testosterone cypionate injection (brand name Depo-Testosterone, among others) is a prescription medication used primarily for testosterone replacement therapy (TRT) in males with a deficiency or absence of endogenous testosterone (hypogonadism). It is administered via deep intramuscular injection. 

Key Information

• Medical Use: The main use is to treat symptoms of male hypogonadism, which can cause low sex drive, erectile dysfunction, loss of muscle mass and body hair, fatigue, and mood changes. It is also used in some cases of delayed puberty in adolescent boys and certain types of breast cancer in women.

• Administration: The injection is typically given deep into a large muscle, such as the gluteal muscle (buttocks). A healthcare professional will often administer the first dose, and may teach patients to self-inject at home. It should not be given intravenously.

• Dosage: The typical dosage for hypogonadism in males ranges from 50 mg to 400 mg every two to four weeks, adjusted by a doctor based on patient response and blood testosterone levels. Some regimens involve smaller doses (e.g., 100 mg) on a weekly basis for more stable hormone levels.