Non-Stim pre workout formulas contain absolutely no traces of jittery stimulants like caffeine. Referred to as "Pump Formulas", non-stim pre-workouts contain nitric oxide boosting properties which will greatly assist your body's ability to shuttle nutrients to your muscles, all while delivering maximum vascularity! Non-Stim pre-workout formulas are often stacked with other, stim-based products in order to completely overhaul your training experience. They're also perfect for athletes who are looking to cycle off of a stim-heavy training routine, but still want the benefits of increased blood flow.