All pre-workouts are not born equal. We've added the most stimulating, caffeine-loaded pre-workout supplement to our C4® ID Series. C4® Extreme Energy is made for your passion, steady drive, and unbroken commitment to your workouts. If you find yourself drinking cup after cup of coffee throughout the day and built your caffeine tolerance above the rest, C4® Extreme Energy is made for you. C4® Extreme Energy features twice as much caffeine, more focus and more endurance than C4® Original. C4® Extreme Energy isn?t for the casual gym goer; it?s for those of you who want to explode through their PRs over and over and over again. Try our delicious flavors, including Cherry Limeade, Icy Blue Razz, and Strawberry Kiwi in 30 servings.