Proviron, the brand name for mesterolone, is a synthetic type of male sex hormone. Mesterolone, chemically known as 1-methyl-5?-dihydrotestosterone (DHT), is methylated (the addition of a methyl group –CH3) making it an active steroid very similar to natural DHT that does not convert into estrogen or progesterone (both female hormones) once in the body. Proviron has many positive effects on the body, including increasing muscle mass, enhancing testosterone levels and treating male sexual dysfunction.
Proviron on its own is considered to be a weak steroid according to a study by A.T. Kicman published in the British Journal of Pharmacology. However, it has unique properties that make it a useful and effective enhancer, especially of testosterone. In normal levels in the body, testosterone is mostly inactive because most of it is bound by sex hormone binding globulin (SHBG) and albumin. Proviron also has a great affinity for SHBG, so when administered, it will bind to the SHBG, leaving more testosterone free.