Proviron acts as an anti-aromatic: it prevents the aromatization (transformation) of anabolic steroids into estrogens. It thus avoids the gynecomastia. It can be combined with Nolvadex to increase its effectiveness. Proviron and Nolvadex are two anti-estrogens whose mechanisms of action are different and complementary, and it is for this reason that the combination of these two products is so effective: while Proviron prevents the use of anti- aromatization of anabolics, Nolvadex obstructs the receptor cells of estrogen, preventing it from acting. It is therefore a formidable tandem.