Mesterolone is an anabolic steroid indicated in the treatment of low testosterone, hypogonadism, oligozoospermia, and Leydig cell failure.
Mesterolone is a synthetic anabolic-androgenic steroid (AAS) and derivative of dihydrotestosterone (DHT). It is inactivated by 3α-hydroxysteroid dehydrogenase in skeleta muscules so it is considered a weak androgen. It is not a substrate for aromatase so it is not converted into estrogen. Mesterolone demonstrated to have minimal effect on sperm counts and levels of FSH or LH. Experiments of mesterolone serving as a potential treatment of depression are still undergoing.
Mesterolone, sold under the brand name Proviron among others, is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of low testosterone levels. It has also been used to treat male infertility, although this use is controversial. It is taken by mouth.
Like other AAS, mesterolone is an agonist of the androgen receptor (AR). Mesterolone is described as a very poor anabolic agent due to inactivation by 3α-hydroxysteroid dehydrogenase (3α-HSD) in skeletal muscle tissue, similarly to DHT and mestanolone (17α-methyl-DHT). In contrast, testosterone is a very poor substrate for 3α-HSD, and so is not similarly inactivated in skeletal muscle. Because of its lack of potentiation by 5α-reductase in "androgenic" tissues and its inactivation by 3α-HSD in skeletal muscle, mesterolone is relatively low in both its androgenic potency and its anabolic potency. However, it does still show a greater ratio of anabolic activity to androgenic activity relative to testosterone.
Mesterolone is not a substrate for 5α-reductase, as it is already 5α-reduced, and hence is not potentiated in so-called "androgenic" tissues such as the skin, hair follicles, and prostate gland.
Mesterolone is not a substrate for aromatase, and so cannot be converted into an estrogen. As such, it has no propensity for producing estrogenic side effects such as gynecomastia and fluid retention. It also has no progestogenic activity.
Because mesterolone is not 17α-alkylated, it has little or no potential for hepatotoxicity. However, its risk of deleterious effects on the cardiovascular system is comparable to that of several other oral AAS.
One of the first and foremost things that Proviron is used for is helping to enhance testosterone levels. It is generally regarded as a weak steroid, but it has a number of interesting applications that can make it useful.
One of the ways that it can increse testosterone is by binding to sex hormone binding globulin, or SHBG. This substance floats around in the bloodstream and picks up excess hormones, such as testosterone. By binding to SHBG, mesterolone is able to help increase the amount of testosterone available in the body.
If you are struggling with hypogonadism, then you will likely experience an increase in testosterone as a result of using mesterolone. This means that you’ll also likely experience an increase in muscle density.
This is because muscle growth is anabolic. By increasing the amount of testosterone available in the body and reducing the impact of SHBG, you will be able to put on more muscle. Furthermore, mesterolone can help to prevent the receptivity of estrogen receptors, preventing this hormone from binding to the muscle tissues in the body.
Furthermore, mesterolone inhibits aromatase, an enzyme that causes testosterone to convert into estrogen. By preventing this, it can help ensure that there is even more free testosterone floating around.
Metabolism: The C1α methyl group of mesterolone inhibits its hepatic metabolism and thereby confers significant oral activity, although its oral bioavailability is still much lower than that of 17α-alkylated AAS. In any case, mesterolone is one of the few non-17α-alkylated AAS that is active with oral ingestion.[2] Uniquely among AAS, mesterolone has very high affinity for human serum sex hormone-binding globulin (SHBG), about 440% that of DHT in one study and 82% of that of DHT in another study. As a result, it may displace endogenous testosterone from SHBG and thereby increase free testosterone concentrations, which may in part be involved in its effects.
Absorption: Well absorbed following parenteral administration.
Route of elimination: Urinary excretion
Half life: Thereafter, drug levels in serum decrease with a terminal half-life of 12 - 13 hours. Mesterolone is bound to serum proteins by 98 %. Binding to albumin accounts for 40 % and binding to SHBG (sex hormone binding globulin) to 58 %. Mesterolone is rapidly metabolised.
All medicines may cause side effects, but many people have no, or minor, side effects. Some medical conditions may interact with Mesterolone.
Tell your doctor or pharmacist if you have any medical conditions.
Side effects of mesterolone include symptoms of masculinization like acne, scalp hair loss, increased body hair growth, voice changes, and increased sexual desire. It has no risk of liver damage.
This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.
