Proviron, also known as mesterolone, is an androgenic-anabolic steroid (AAS) that is used primarily for treating low testosterone levels in men. It is not typically used for building muscle or increasing athletic performance like other AAS, but rather for its anti-estrogenic properties.

Proviron works by binding to the aromatase enzyme, which is responsible for converting testosterone into estrogen. By blocking this conversion, Proviron can help prevent estrogen-related side effects such as water retention, gynecomastia (breast tissue enlargement), and decreased libido.

Proviron is taken orally and has a half-life of approximately 12 hours. It is usually taken in doses of 25-100mg per day for a period of 4-6 weeks. Some bodybuilders and athletes also use Proviron during steroid cycles to reduce estrogen-related side effects and to enhance the effects of other AAS.

It is important to note that Proviron can have potential side effects, including acne, hair loss, and increased aggression. It should only be used under the guidance of a medical professional and with careful monitoring. Additionally, Proviron is a controlled substance in some countries, and its use without a prescription may be illegal.