Stanozolol is a synthetic anabolic steroid derived from testosterone, and has been approved by the FDA for human use. Unlike most injectable anabolic steroids, stanozolol is not esterified and is sold as an aqueous suspension, or in oral tablet form. Stanzolol has high bioavailability due to a C17 ?-alkylation which allows the hormone to survive first-pass liver metabolism when ingested. It is because of this that stanozolol is also sold in tablet form. Stanozolol is popular among bodybuilders and professional athletes, some of whom have been fined for using banned performance enhancing drugs.