Fuckin love them. Didnt notice anything on 200mcg but 400mcg was the magic number for me. i dont think i have ever done so many sets for legs in my life. Normally you get that urge for just 1 more rep, just 1 more. with this shit your like just 10 more sets of 10, that all. lol. Just train smart and dont try to max out everything you do. It give you and incredible push. Not agressive or angry just a motivated type of feeling for prob 2- 2.5 hrs.