Fluoxymesterone

Fluoxymesterone (trade name Halotestin) is an anabolic steroid with strong androgenic properties that has been used in the treatment of male hypogonadism, delayed puberty in males, and in the treatment of breast neoplasms in women. It is approximately 5 times as potent as testosterone. The antitumor activity of fluoxymesterone appears related to reduction or competitive inhibition of prolactin receptors or estrogen receptors or production. Dissimilar to testosterone, halotestin has a 100% bioavailability, as the methylation of the 17α-position in halotestin inhibits hepatic metabolism by enzymatic oxidation of 17β-hydroxyl, allowing its absorption into the bloodstream for transport around the body. While there are many legitimate pharmaceutical applications of halotestin, it is also abused, leading to the development of analytical techniques by which halotestin doping can be identified.