MENT (7alpha-methyl-19-nortestostrone), or trestolone was one of several 19-nortestosterone derivatives to be investigated as a possible male contraceptive therapy due to its unique chemical properties. Initially, drug companies were combining progesterone with testosterone in order to produce a viable male contraceptive option due to progesterone's ability to suppress spermatogenesis.
While testosterone can decrease sperm production, the dose for a test-only birth control would be too high to avoid unwanted side effects.
Testosterone can also convert to DHT via 5alpha-reductase, it can have deleterious effects on the prostate, as well as increase male pattern balding. Since MENT was incapable of binding to 5alpha-reductase and thus cannot convert to DHT, it made it a perfect candidate for an androgen male contraceptive.
The reason for this lies in the unique alpha-methyl group on carbon 7 of the molecule. This methyl group sticks out below the steroidal ring structure and sterically inhibits the conversion to DHT. However, MENT still can undergo aromatization and undergo other androgen-dependent functions, making it effectively act like testosterone in the body despite being a 19-nortestosterone derivative.
MENT was also shown to have minimal affinity for the progesterone and mineralocorticoid receptors, despite being a nandrolone derivative.
Another unique property of MENT's 7alpha-methyl group is it also can inhibit binging of MENT to sex hormone binding globulin (SHBG), a protein that binds with androgens (and estrogen) so that they can no longer bind to the androgen receptor. If you have ever gotten your testosterone levels check, you will see 2 values: total and free testosterone.
Free testosterone is the amount of testosterone that is NOT bound to SHBG and is "free" to bind to the androgen receptor and elicit its effects. By MENT not being able to bind to SHBG, it is essentially free to only bind to the androgen receptor and yield the benefits of exogenous androgen use. This makes MENT a very attractive option when looking to not only add quality muscle, but also keep your sex drive high and not make any unwanted babies.
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