D-Ribose has been shown, with positive results, to generate ATP recovery -- leading to improved health and fitness for people with cardiovascular problems, athletes who deplete their energy reserves, and those with fibromyalgia and CFS. Reports have shown d-ribose can even lower blood sugar levels and is also known to alleviate altitude sickness and PMS cramping. Ribose, primarily occurring as D-ribose, is an organic compound that occurs widely in nature. It is an aldopentose, that is a monosaccharide containing five carbon atoms that, in its acyclic form, has an aldehyde functional group at one end. Typically, this species exists in the cyclic form, as depicted in the upper right. It was first reported in 1905 by Phoebus Levene. It comprises the backbone of RNA, a biopolymer that is the basis of genetic transcription. It is related to deoxyribose, as found in DNA, by the removal of one hydroxy group. Ribose is also a subunit of ATP, NADH, and several other compounds that are critical to metabolism.