However, paradoxically, a case report of severe fluoxymesterone-induced gynecomastia exists, and gynecomastia associated with fluoxymesterone has also been reported in other publications, although this may not be due to estrogenic activity. Fluoxymesterone is thought to possess little or no progestogenic activity.Because of the presence of its 17α-methyl group, the metabolism of fluoxymesterone is impeded, resulting in it being orally active, although also hepatotoxic. 11β-HSD inhibition
Fluoxymesterone has been found to act as a potent inhibitor of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) (IC50 = 60–630 nM), with a potency comparable to that of the 11β-HSD2 inhibitor glycyrrhetinic acid. This action of fluoxymesterone is unique among AAS and is likely related to its 11β-hydroxyl group. 11β-HSD2 is responsible for the inactivation of the glucocorticoids cortisol and corticosterone (into cortisone and 11-dehydrocorticosterone, respectively). Inhibition of 11β-HSD2 by fluoxymesterone may result in mineralocorticoid receptor overactivation and associated side effects such as hypertension and fluid retention, and has been hypothesized to be involved in the cardiovascular and other adverse effects of fluoxymesterone. Glucocorticoid activity
Unlike other AAS, fluoxymesterone has structural features in common with corticosteroids, including its C9α fluoro and C11β hydroxyl groups. In relation to this, it has weak (micromolar) but potentially clinically significant affinity for the glucocorticoid receptor. Pharmacokinetics
Fluoxymesterone has approximately 80% oral bioavailability, unlike testosterone, as the C17α methyl group of fluoxymesterone inhibits first-pass metabolism. It has very low affinity for human serum sex hormone-binding globulin (SHBG), less than 5% of that of testosterone and less than 1% of that of DHT.
Halotestin and many of its metabolites contain two polar hydroxyl groups, leading to intermolecular hydrogen bonding that increases their boiling point and reduces volatility. In order to attain a gaseous sample for GC-MS, the products of hydrolysis are extracted, dissolved in methanol and derivatised to form volatile trimethylsilyl (TMS) esters by adding N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) and trimethylsilylimidazole (TMSImi). History
Fluoxymesterone was first described in 1956 and was introduced for medical use in the United States in 1957. Over time the use of fluoxymesterone has become increasingly controversial and limited. Society and culture
Generic names
Fluoxymesterone is the generic name of the drug and its INN, USP, BAN, DCIT, and JAN, while fluoxymestérone is its DCF. Brand names
Brand names of fluoxymesterone include Android-F, Androxy, Halotestin, Ora-Testryl, and Ultandren among others. Availability
United States
Fluoxymesterone is one of the few AAS that remains available for medical use in the United States. The others (as of November 2017) are testosterone, testosterone cypionate, testosterone enanthate, testosterone undecanoate, methyltestosterone, oxandrolone, and oxymetholone. Other countries
Availability of fluoxymesterone aside from the United States remains scarce, but it is marketed in some other countries such as Mexico, Moldova, and Taiwan. Legal status
Fluoxymesterone, along with other AAS, is a schedule III controlled substance in the United States under the Controlled Substances Act. References


== External links ==