Right now, i've only been using it for about 5 weeks, but i will be on it for the duration of my off-season, then continue it for contest prep. That will be a total of about 7 months. My dose is 400/wk right now, but i'm slowly working my way up to 600/wk. I get bloodworkd done every 3 months as well, so next month i'll know what it's doing to me. I don't anticipate any issues, because i used 450/wk for 3 months during my last contest prep without any ancillaries and everything bloodwork-wise was great.