Proviron is a modified form of dihydrotestosterone. Due to the addition of the methyl group to carbon 1, this drug differs from dihydrotestosterone, which protects the hormone from metabolism in the liver by oral administration. In oral tablets Primobolan (methenolone) the same structural modification is applied. Already after the first administration of the drug, 1-position alkylation slows the hepatic metabolism of steroids, albeit to a much lesser degree than with c-17 alpha alkylation. Mesterolone is an androgen, as well as dihydrotestosterone, and its anabolic activity is manifested at a weak level.
Mesterolon is a modified form of dihydrotestosterone. It differs from dihydrotestosterone by adding a methyl group to carbon 1, which helps protect the hormone from metabolism in the liver by oral administration. The same structural modification is also used in orally administered Primobolan tablets (methenolone). Alkylation slows the hepatic steroid metabolism by one position at the first application, although much less than with c-17 alpha alkylation. Mesterolone has sufficient resistance to disintegration, which makes it possible to reach therapeutically useful levels in the blood, although the drug has a much lower overall bioavailability than the 17 alpha-alkaline steroids used orally. Mesterolone also has a very strong affinity for the globulin binding sex hormones. It can act by displacing other steroids that are loosely associated with SHBG in the free (active) state.
Side Effects It should be noted that despite its “softness” – proviron is capable of causing serious side effects. For example, its androgenic activity can serve as an impetus to the development of prostatic hypertrophy and male pattern baldness. It is also noted that if there is a significant excess of therapeutic dosages, the risk of toxic effects on the liver and the appearance of tumor processes in it increases.