D-ribose is a simple five-carbon sugar that is produced naturally in the body. It a key component of DNA, ribonucleic acid (RNA), acetyl coenzyme A, and ATP.
[Understanding D-Ribose and Mitochondrial Functionhttps://www.ncbi.nlm.nih.gov > articles > PMC5959283].

D-ribose supplementation is sometimes recommended by Naturopathic Medical Doctors (NMD), such as Dr. Weyrich, to boost mitochondrial energy production of ATP.