What is "dienedione"

Dienedione, also known as estra-4,9-diene-3,17-dione is an anabolic steroid. It became a controlled substance in the US on January 4, 2010, and is classified as a Schedule III anabolic steroid under the United States Controlled Substances Act. Previous to this, it was sold as a bodybuilding supplement within the United States, and often mistakenly marketed as a prohormone for trenbolone, a veterinary steroid. Prior to its scheduling, it was part of a number of supplements that were seized during FDA enforcement of Bodybuilding.com for selling unapproved new drugs. The actual target steroid, dienolone has some structural similarity to trenbolone, but lacks the 11-carbon -ene bond.