Being someone who takes hard hitters and can't function off any less than 600 mg of caffiene a day, the stims in this were very very light. However, this pre workout wasn't designed to be for stim junkies and was more geared towards endurance and long training sessions. It surely did its job and I had the focus the label was built for, but a part of me wishes the stims were just a little higher... (maybe some alpha yo...?). Regardless, great preworkout and a really good daily endurance driver, provided you're willing to use such an expensive pre for that.