Trenbolone was first described in 1967. This is an extremely strong anabolic steroid, 19-nor modification of testosterone, but with by five times stronger both anabolic and androgenic activity.

Trenbolone is a steroid anabolic. Being actually a derivative of nandrolone, trenbolone is strikingly different from the latter in properties. Due to the nature of the structure, trenbolone is not exposed to 5α-aromatase, but by itself can exhibit both estrogenic and progestogenic activity (the latter is expressed in the ability to activate progesterone receptors). Trenbolone is the most powerful of the anabolic steroids that are currently available - Trenbolone is not only more than three times more testosterone (and more than three times) than nandrolone to stabilize the androgen receptor.

Trenbolone greatly increases the level of the extremely anabolic hormone IGF-1 (insulin-like growth factor) within muscle tissue (up to 200%). And, it’s worth noting that not only does it increase the levels of IGF-1 in muscle over two fold, it also causes muscle satellite cells to be more sensitive to IGF-1 and other growth factors. The amount of DNA per muscle cell may also be significantly increased.