Klean Endurance contains pure D-Ribose to support the natural process by which a body produces adenosine triphosphate (ATP). The naturally-occurring pentose sugar supports cardiovascular health, energy production and mitochondrial function. Available in a great-tasting chewable tablet, Klean Endurance offers a clinically proven method to help restore energy during exercise.Key BenefitsD-Ribose is the critical building block for producing ATP, the energy currency of the cell. Supplementing with D-Ribose allows the muscles to bypass the slow, rate-limited process of making ribose from glucose, thereby accelerating energy synthesis and recovery Great-tasting Chewable Tablet