note
One major problem with Proviron is that it tends to reduce the gains made from a cycle. This is due to the fact that Proviron is an androgen and therefore binds to androgen receptor sites within the body. With Proviron binding to androgen receptor sites, the other steroids present in the body (androgens) are blocked out and unable to take effect. Consequently, many athletes prefer to keep the intake of Proviron at its minimum effective dosage in order to make sufficient gains while still preventing gynecomastia.