XTEND® Energy is designed to help you power through those moments. Unlike other energy-infused amino acids, XTEND® Energy provides a combination of fast-acting fuel and time-released caffeine to keep your workout performing at its best, for longer. With ZümXR® delivering caffeine for up to 6 hours after your first sip, you can count on XTEND® Energy to work as hard as you do, for the longest workouts.