Klean Endurance is a great-tasting chewable tablet that contains pure, all-natural D-Ribose to support the natural process by which a body produces adenosine triphosphate (ATP). These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. | 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. These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.