Proviron (Mesterolone) is an oral anabolic and belongs to the steroids category. Many would not believe that because of its great anti-estrogenic properties and no influence on the liver. It is not liver toxic because it is not 17alpha alkylated, which is the molecule that makes orals liver toxic. Let’s be honest and say that Proviron has very few benefits but still important for a bodybuilder, however, you can replace it with other products like SERMS (Selective estrogenic receptor modulator) or AI´s (Aromatase inhibitors) anytime. This is because it is really not the best option to fight estrogenic side effects even it has strong effects on water retention, libido, blood pressure and Gynecomastia (male tits). Just keep in mind that it is better than nothing. Another reason why you should use Proviron is because the ability to make more free testosterone so that your steroids works even better, yes, they will work better because Proviron binds to the SHBG (sex hormone-binding globulin) the plasma carrier of sex hormones and makes it possible for other steroids to produce more free testosterone that is necessary to build muscles. Proviron is not useful on its own, so you cant take just the Proviron without other Steroids and it is recommended to use it during the cycle and not for PCT or bridge.