Instone Forza-T - From Sylvester Stallone - Maximize Your Natural Testosterone Levels And Stop Estrogen! Scientifically designed combination of 6-OXO, Tribulus, and ZMA to kick-start your body's own production of testosterone. Forza-T is the only product to combine these three distinct mechanisms for maximum testosterone boost. This formula has been shown to be a potent inhibitor of the aromotase enzyme to naturally decrease estrogen levels and is clinically tested and shown to increase free-testosterone levels by up to 226%, the active and unbound form of testosterone that can truly make the difference in performance.