Stanozolol (abbrev. Stz), sold under many brand names, is an androgen and anabolic steroid (AAS) medication which was derived from dihydrotestosterone (DHT). It was developed by American pharmaceutical company Winthrop Laboratories (Sterling Drug) in 1962, and has been approved by the U.S. Food and Drug Administration for human use, though it is no longer marketed in the USA. It is also used in veterinary medicine. Stanozolol has mostly been discontinued, and remains available in only a few countries. It is given by mouth in humans or by injection into muscle in animals.