Proviron
Proviron, also known as Mesterolone, is an oral androgenic steroid primarily used to treat low testosterone levels and male infertility caused by hormonal imbalances. In bodybuilding, Proviron is valued for its ability to enhance muscle hardness, boost libido, and improve overall physique without significant water retention. It binds strongly to androgen receptors, promoting fat loss and increasing the effectiveness of other anabolic steroids by reducing estrogenic activity.

Proviron does not convert to estrogen, making it effective in preventing gynecomastia and reducing water retention caused by aromatizing steroids. It also increases free testosterone levels by binding to sex hormone-binding globulin (SHBG), which allows more active testosterone to circulate in the body. While it is relatively mild, prolonged use can lead to side effects such as hair loss, acne, and suppression of natural testosterone production. It is often used as a supportive compound during cycles rather than for muscle growth. Post-cycle therapy (PCT) is still recommended after its use to restore hormonal balance.