Well I took only 3the other day with some food and loads of water before and throughout my workout like always. I felt absolutely amazing. The focus thing is unreal. I got so into the zone I walked out of the gym kinda confused almost with what I had just done because I was so focused on only lifting. Gave me a nice little endurance boost and great pump. I am very sensititve to stims so i should have known to start lower than recommended. I think I could tolerate a little bit more as long as I have soething in my stomach and drink a lot of water. Great product so far though.