Sustanon is a solution in oil that contains testosterone esters, including testosterone propionate, phenylpropionate, isocaproate, and decanoate. It is used in adult men for testosterone replacement to treat various health problems caused by a lack of testosterone, such as male hypogonadism. Sustanon may also be used as supportive therapy for female-to-male transsexuals. It is administered by deep intramuscular injection. Sustanon injections help to increase testosterone levels, which is essential for sperm production, sex drive, getting an erection, and the functioning of the prostate gland and other reproductive structures. However, the misuse of Sustanon to enhance athletic performance carries serious health risks and is discouraged. Sustanon injections are on the list of substances banned in sport by the World Anti-Doping Agency (WADA) .