Ribose (D-Ribose) is an organic compound (3-carbon carbohydrate) that is involved in the synthesis of adenosine triphosphate (ATP – Pic. 1) in the muscle (the useable form of energy). People take ribose for several reasons, most often related to exercise. Manufacturers most often claim that it can improve endurance and energy, reduce muscle fatigue and increase post-workout recovery. It can be found in plants as well as animals, however, you can’t get enough from food sources to meet the doses recommended by supplement manufacturers .
Pic. 1 – ATP structure
Ribose effectiveness – Confusing results
Ribose has shown some promise for people with coronary heart disease . For this reason, ribose has been suggested to be an anabolic agent and ergogenic aid for athletes. However, most studies show no ergogenic benefits for exercise capacity. Keksick and colleagues  and Kreider and others  all evaluated the potential ergogenic value of oral D-ribose supplementation on measures of anaerobic capacity in trained athletes. Both studies reported that oral ribose supplementation does not have substantial effects on anaerobic exercise.
One other study also showed that oral ribose supplementation with 4 g doses four times a day has not beneficially impact on post-exercise muscle ATP recovery . However, researchers from Institute for Exercise and Sport  demonstrated that oral intake of ribose in humans after 1 week of high-intensity training leads to an enhanced resynthesis of ATP.
Ribose vs. Dextrose
People often ask which is better – ribose or dextrose. As previously stated some studies have reported that ribose supplementation may rapidly replenish adenosine triphosphate stores and thereby improves exercise performance. In the light of this, Laura Dunne et al.  compared the effects of ribose versus dextrose on rowing performance. Ribose and dextrose were supplemented 10 g each for 8 weeks before and after practice. In the time trials, the dextrose group showed significantly more improvement at 8 weeks than the ribose group (P = 0.031).
According to current research available it seems that ribose supplementation does not improve aerobic or anaerobic performance.
Ribose side effects
The safety of ribose has not been fully established. Some people report side effects such as: diarrhea, gastrointestinal discomfort, nausea and headache. It may also cause low blood sugar when combined with diabetes drugs. WebMD.com  also suggests that ribose should be avoided a few weeks before surgery.
Kreider, Richard B., et al. “ISSN exercise & sport nutrition review: research & recommendations.” J Int Soc Sports Nutr 7.7 (2010).
Pliml, Wolfgang, et al. The Lancet 340.8818 (1992): 507-510.
Kerksick, C., et al. “Effects of d-ribose supplementation prior to and during intense exercise on anaerobic capacity and metabolic markers.” International journal of sport nutrition and exercise metabolism 15.6 (2005): 653.
Kreider, R. B., et al. “Effects of oral D-ribose supplementation on anaerobic capacity and selected metabolic markers in healthy males.” International journal of sport nutrition and exercise metabolism 13 (2003): 76-86.
- Op’t Eijnde, B., et al. “No effects of oral d-ribose supplementation on repeated maximal exercise and de novo ATP resynthesis.” Journal of Applied Physiology 91.5 (2001): 2275-2281.
- Hellsten, Ylva, L. Skadhauge, and Jens Bangsbo. “Effect of d-ribose supplementation on resynthesis of adenine nucleotides after intense intermittent training in humans.” American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 286.1 (2004): R182-R188.
- Dunne, Laura, Sarah Worley, and Michael Macknin. “Ribose versus dextrose supplementation, association with rowing performance: a double-blind study.” Clinical Journal of Sport Medicine 16.1 (2006): 68-71.
- Vitamins & Supplements – WebMD Retrieved 10. April 2013