Fluoxymesterone is among the harshest oral androgens in circulation. It is 17-alpha-alkylated so that it survives the liver's first pass, halogenated with fluorine at the ninth carbon, and strongly androgenic while contributing very little to muscle tissue growth. Medically it has featured in hypogonadism treatment and in certain breast-cancer protocols.
Alpha Pharma's version is Halobol, fifty tablets of 5 mg, the lower of the two tablet strengths on the market. The alkylation that makes the compound orally active is also what makes it hepatotoxic.
