Dienedione, also known as estra-4,9-diene-3,17-dione, is a synthetic, orally active anabolic-androgenic steroid (AAS) of the 19-nortestosterone group that was never introduced for medical use. It is thought to be a prohormone of dienolone, it was sold as a bodybuilding supplement within the United States, and often mistakenly marketed as a prohormone for trenbolone, The actual active metabolite, dienolone, is almost identical to trenbolone structurally, but lacks the C11 double bond. So they are different compounds.