Fluoxymesterone is an oral anabolic steroid derived from testosterone. More specifically, it is a methyltestosterone derivative, differing bye the addition of 11-beta-hydroxy and 9-alpha-fluoro groups. The result is a potent orally active non-aromatizable steroid that exhibits extremely strong androgenic properties. Fluoxymesterone is considerably more androgenic than testosterone, while at the same time the anabolic effects of this agent are considered to be moderate in comparison. This makes fluoxymesterone a great strength drug, but not the most ideal agent for gaining muscle mass. The predominant effects seen when taking fluoxymesterone are increased strength, increased muscle density, and increased definition, with only modest size increases.