I've used it for months on end many times over.. 20-30mg pre-workout ONLY.. bloods were always good.. anything higher I shorten it, 50+ mgs I'll go 6-8 weeks.. at higher dosages it seems to lose its effect relatively quick, compared to lower dosages.. lower dosages is good for maintenance and a pump.. keep in mind that I blast and cruise, and I get blood work just about every 6 weeks..