Methylclostebol, also known as 4-chloro-17α-methyltestosterone or as 4-chloro-17α-methylandrost-4-en-17β-ol-3-one, is a synthetic, orally active anabolic-androgenic steroid (AAS) and designer steroid that has been sold on the Internet as a "dietary supplement", but it has never been studied for medical use. It is the 17α-alkylated variant of clostebol (4-chlorotestosterone).