Ribose is a naturally occurring sugar made in the body from glucose and is an essential component of ATP (adenosine triphosphate), the compound that stores and delivers energy in all cells. Ribose also occurs in RNA (ribonucleic acid), one of the main information-carriers of living organisms. Because ATP is rapidly used by muscles in high-intensity workouts and because RNA is important in protein synthesis, ribose supplements and energy drinks containing ribose are being promoted for energy enhancement and better exercise performance. The supplements are said to speed muscle tissue recovery after exercise, and limit post-exercise fatigue.

Ribose supplements haven't been extensively studied, but emerging evidence does suggest that they benefit patients with congestive heart failure, a serious condition in which the heart cannot pump sufficient blood to meet the body's circulatory needs. In a study in The European Journal of Heart Failure, ribose appears to improve heart function and quality of life among these patients by increasing levels and availability of ATP. Patients with congestive heart failure (or other forms of heart disease) should discuss ribose supplementation with their physicians. The supplements appear safe and side effects, if any, are minimal: lightheadedness and mild diarrhea. The maximum recommended dose is five grams three times a day, taken with food.

Preliminary evidence also indicates that ribose may ease the pain and fatigue of patients with fibromyalgia and chronic fatigue syndrome. In one small study published in the November 2006 issue of The Journal of Alternative and Complementary Medicine, patients who took five grams of ribose three times a day for an average of 28 days reported less muscle soreness and stiffness, better ability to overcome fatigue, and simply feeling better. While encouraging, this study had its limitations: there was no placebo group or long-term follow up. Further studies suggest that ribose may also help improve exercise tolerance in high intensity activities, and I would like to see more studies to evaluate the effectiveness of ribose in these groups of patients.

Although ribose is essential for energy production, the body does not recognize it as a fuel, so it actually is of no caloric value to humans. Even so, because it is chemically a sugar, the FDA requires that calories be identified on the product label. Ribose taken at the recommended dose is unlikely to do you any harm, but you should be aware that it is being added to many products, including energy drinks, and you may be getting more than you think. If ribose is working for you I would limit your intake of it to no more than five grams three times day.

Andrew Weil, M.D.