Well so far so good. I like the stack. I can say that the amp doesnt give me the extreme energy that I heard some say. BUT my endurance is up 10 fold and focus is great. I now have to make myself leave the gym whereas before my body would would fatigue and make me leave. My strength is steady rising each week as well. So needless to say I am please with the stack, especially at the price. I up'd the dosage to 9 and I really didn't see much different from 6, as far as energy is concerned. So I take 6 with a cup of coffee about 30-45 mins. before I lift. I also found that taking the MCC and AMP at the same time works better for me.