USP recommends 8 weeks on, 4 weeks off on its forum. I run my Jack3d 6 weeks on, 3 weeks off. This way I can start each cycle with 1 scoop giving me the full effect, and end each cycle with 3 scoops giving the full effect. I would recommend using it until either you reach 8 weeks or 3 scoops doesn't do it for you anymore, then take 3-4 weeks off.