A-dex takes awhile to work in your system and eliminates Estrogen all together (or at least begins to minimize it). Nolva works immediately however to block Estrogen receptors in mammary tissue, thus reducing bitch tits from the start. If you already have gyno signs, then Nolva is the preferred method for reduction....it will not do much, if anything, for already developed breast tissue. It does do wonders for the majority on sore, itchy nips asociated with early gyno symptoms.