Fluoxymesterone (FMT)

Long term daily administration of fluoxymesterone (9alpha-fluoro-17alpha-methyl-11beta, 17beta-dihydroxyandrost-4-en-3-one) was associated with a modest suppression of sperm production and a profound suppression of testosterone levels in the absence of significant effects on plasma gonadotropin levels. Fluoxymesterone 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 methyltestosterone. The antitumor activity of fluoxymesterone appears related to reduction or competitive inhibition of prolactin receptors or estrogen receptors or production. Like many C-17 alpha alkylated steroids, fluoxymesterone has poor binding to the androgen receptor.