Trenbolone is a 19-nor derived steroid, in the 19-nor Testosterone (Nandrolone) family. In fact, Trenbolone is structurally similar to Deca Durabolin, differing in the fact that it has a c-9 and c-11 double bond. The c9 bond serves to prevent any aromatization (conversion) to estrogen, and thus we see far less water retention with Trenbolone when we compare it to Deca-Durabolin. Unlike nandrolone however The c11 double bond also seems to increase Androgen Receptor binding quite profoundly (this may also have something to do with the c9 bond as well). This lack of estrogenic activity and powerful ability to bind to the androgen receptor combine to make Trenbolone a much more powerful androgen than Deca, however. It also virtually eliminates all water gain and makes the majority of weight gained on this drug (at least in animal studies) virtually all new, quality muscle. (1) This has been anecdotally replicated in human "studies" (read: athletes who use Trenbolone) many times over. British Dragon Gear produces our brand of Trenbolone called Tren Fina™.