D-Ribose is a naturally occurring monosaccharide. It has been the subject of much research for its reputed role in cardiac and cellular energy metabolism. The human heart beats about 100,000 times daily, pumping roughly 2,000 gallons of blood. To do this amount of work, the heart requires about 13 lbs (6 kilos) of ATP daily, more than any other organ. D-Ribose may help by providing nutritive support for the synthesis of ATP, which is crucial in intracellular energy transfer.