Ribose is a type of sugar used by the body to make the energy-containing substance adenosine triphosphate (ATP). Intense exercise depletes muscle cells of ATP as well as the ATP precursors made from ribose,^{1, 2} though these deficits are typically replaced within minutes.³ Unpublished reports suggested that ribose supplementation might increase power during short, intense bouts of exercise.^{4, 5} However, in a double-blind study, exercisers took 4 grams of ribose four times per day during a six-day strength-training regimen, and no effects on muscle power or ATP recovery in exercised muscles were found.⁶ In two other controlled studies, either 10 grams of ribose per day for five days or 8 grams every 12 hours for 36 hours resulted in only minor improvements in some measures of performance during repetitive sprint cycling.^{7, 8}