Among commonly used oral AAS, dianabol has 2 times the anabolic activity of testosterone, anavar, winstrol, anadrol has 3 times the anabolic activity of testosterone, superdrol has 4 times the anabolic activity of testosterone, and Mesterolone has the same anabolic activity as testosterone. In this case, why choose Mesterolone for bodybuilding?
First of all, it doesn't aromatize, it doesn't convert to estrogen. This is something that many other oral AAS can do.
Second, it does not aromatize and inhibits the action of aromatase, acting as a certain anti-estrogen agent, something that most oral AAS do not do.
Finally, it does little to suppress endogenous testosterone levels, something other oral AAS do not do at all.
Whether Mesterolone inhibits aromatase or does not inhibit endogenous testosterone, it is related to its high affinity.
Mesterolone has a high affinity with aromatase and binds to aromatase preferentially over other AAS, including testosterone, thereby reducing the concentration of aromatase in the body and preventing other AAS or testosterone from binding to aromatase to produce estrogen.
Mesterolone has a high affinity with SHBG (human serum sex hormone binding protein). It does not compete for androgen receptors with other AAS or free testosterone, so that other AAS or free testosterone can better bind to the androgen receptor and play a role. Because of its high affinity, Mesterolone is consumed quickly in the body without inhibiting endogenous testosterone levels.
In addition to not competing for androgen receptors, it also causes the body to release more free testosterone. In the body, the percentage of free testosterone is only about 2% of the total testosterone level, about 50% of which tightly bind to SHBG, become unavailable testosterone. When Mesterolone levels rise, it preferentially binds to SHBG and releases more free testosterone. More free testosterone binds to more androgen receptors to grow muscle.
When using with more powerful AAS, Mesterolone works better by reducing the amount of other AAS that consum by aromatase or SHBG.
Therefore, Mesterolone is not a powerful AAS, but a safer and more versatile AAS.