Testosterone Propionate is an androgen and anabolic steroid medication which is used mainly in the treatment of low testosterone levels in men. Low testosterone levels in males can lead to mood changes, poor concentration, erectile dysfunction (trouble getting or keeping an erection), and low sex drive. It can also cause reduced growth of penis and testicles, gynecomastia (breast growth), loss of body hair and muscle mass, anemia, and osteoporosis.