1,4,6-Androstatriene-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 estrogen synthesis.

ATD is present in some over-the-counter bodybuilding supplements as well as Topical ATD solutions that work transdermally. While not banned, ATD may cause positive urinalysis results leading to disqualification from competitive sports.[citation needed]ATD has many names in sports supplements including: 1,4,6 etiollochan-dione, 3, 17-keto-etiochol-triene, androst-1,4,6-triene-3,17-dione and many others. These all refer to CAS# 633-35-2.

ATD may cause a positive test for the steroid raw powder bold, of which it is a metabolite and is also prohibited in amateur and professional sports which forbids aromatase inhibitors.

1,4,6-Androstatrien-3,17-dione (ATD) offers benefits such as improvements in male fertility, mood levels, shortened recovery in case of burns or severe trauma and stimulation in developing mammals. It is considered to be a more effective anti-aromatase substance than many others and is potent enough to increase test levels in the body without a concomitant reduction of the estrogen levels in men. It may be used for hormone or androgen replacement therapy in men without resulting in a concomitant reduction in endogenous estrogen levels when administered in an oral or transdermal way in dosages ranging from 25-150 mg/day.