1,4,6-Androstatrien-3,17-dione (ATD) is a potent irreversible aromatase inhibitor that inhibits estrogen biosynthesis by permanently binding and inactivating aromatase in adipose and peripheral tissue. It is used to control estrogensynthesis.ATD is present in some over-the-counterbodybuilding supplements such as Rebound XT, Novedex XT and Inhibit-E. While not banned, ADT may cause positive urinanalysis results leading to disqualification from competitive sports due to its similar properties to banned substances.A related agent is exemestane (Aromasin).
See more at Wikipedia.org...