Trenbolone Enanthate is a strictly underground product, and not available for human use by any major pharmaceutical supply house in the world. It combines a very popular parent hormone (trenbolone) with a long acting ester (enanthate). This allows the advantage of once a week injections. For a fairly long time, the only version of legitimate Trenbolone available on the black market was Trenbolone Acetate. This was a fast acting version of Trenbolone often made from powder or cattle implant pellets. Since Parabolan (Trenbolone with a slightly longer ester) had been removed from the market, it developed a cult-like reputation, and a longer acting Trenbolone product was in demand on the black market. The underground labs of the time responded with Trenbolone Enanthate.