Halotestin is an anabolic steroid with a very strong androgenic activity, derived from methyltestosterone. The clinical purpose of fluoxymesterone consisted originally in the treatment of male hypogenitalism, delayed puberty in men, and in the treatment of breastneoplasms in women.

Due to its specific fluoxymesterone is mainly used by athletes to enhance the power performance, muscle hardness and aggression without increasing the overall weight; it is used as well in box and other combat sports. In bodybuilding fluoxymesterone is used rarely, because it does not promote significant muscle bulking.

Fluoxymesterone does not aromatize and does not convert to estradiol; however, this is a very potent androgen. Female athletes should stay away from the drug.

Fluoxymesterone has an interesting feature: it activates erythropoiesis (production of red blood cells) and enhances the branching of the capillary network in muscles, and as result of improved blood supply significantly increases strength and endurance.