Background
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.
Steroid Action
Trenbolone Enanthate is a19-nor steroid, very similar to Nandrolone. The primary difference between Trenbolone is that there is a double carbon bond present at the 9 and 11 position on the steran nucleus. Trenbolone can not aromatize to estrogen nor be 5a-reduced.
It bonds very tightly to the Androgen Receptor, and for this reason it is thought that much of its fat-burning and muscle building abilities are receptor mediated.
Technical Data
Trenbolone Enanthate use produces an impressive amount of new muscle fiber, with minimal water retention (1) This may be done partly through an increase in IGF-1 within muscle tissue (2), and increased sensitivity of muscle satellite to IGF-1 and other growth factors(3) and an increase in the amount of DNA per muscle cell.
It has a very strong binding affinity to the androgen receptor (A.R), binding much more strongly than testosterone (4) as well as nandrolone.
Trenbolone increases both protein synthesis as well as nitrogen retention in muscle tissue (5). Trenbolone can also bind with the (anti-anabolic) glucocorticoid receptor (6-7), thus aiding the muscle building process.
Finally, it also has the ability to improve nutrient efficiency and mineral absorption in animals given the drug (8-9).