Methandienone (also known as methandrostenolone, Dbol, dianabol) is an orally-effective anabolic steroid originally developed in Germany and released in the US in the early 1960s by Ciba Specialty Chemicals. This is a derivative from testosterone, one of the most popular steroid compounds in the world and the second steroid (after testosterone) ever produced. Methandienone promotes dramatic increases in protein synthesis, glycogenolysis, and muscle strength over a short space of time.  

It also has the effect of decreasing the steroid's affinity for sex hormone binding globulin. As a result, methandrostenolone is significantly more active than an equivalent quantity of testosterone, resulting in rapid growth of muscle tissue. However, the concomitant elevation in estrogen levels - a result of the aromatization of methandrostenolone - results in significant water retention. Hence, do not forget to perform blood works and use an aromatase inhibitor.

In summary, this is a very good drug, and a potent tool for quick gains or retaining gains when used properly and safely.