Azacosterol, or azacosterol hydrochloride, also called 20,25-diazacholesterol, is a cholesterol-lowering drug (hypocholesteremic), which was marketed previously, but has since been discontinued. It is also an avian chemosterilant used to control pest pigeon populations via inducing sterility. The drug is a sterol and derivative of cholesterol in which two carbon atoms have been replaced with nitrogen atoms.