D-Ribose Powder 200 grams from Source NaturalsD Ribose Powder Enhances ATP Energy Levels. A simple sugar used by the body to synthesize ATP, as well as nucleotides, nucleic acids, and glycogen. During strenuous exercise, large amounts of ATP, the body's primary energycarrying molecule, can be depleted from the heart and skeletal muscle cells. Shown in a preliminary pilot study to address muscle fatigue and cellular energy metabolism. Available in powder and fruit flavored chewable tablets.