Ribose is a carbohydrate vital for the body's manufacture of ATP (adenosine triphosphate), which is the major source of energy used by our cells.

Quite a few studies have been done on ribose, mostly relating to its potential usefulness for individuals with heart disease. When the heart is starved for oxygen, as can occur with a heart attack or angina, it loses much of its ATP, and its ATP levels remain low for several days, even after blood flow is resumed.1 Scientists have found that supplying extra ribose in the blood helps restore the heart's normal ATP levels more quickly. This finding has raised hopes that ribose supplements might improve heart functioning and increase exercise capacity.

Ribose is better known as a sports supplement. However, current evidence indicates that it is not effective for this purpose.

Requirements/Sources

Ribose is not an essential nutrient. Although it is a common sugar present in the bodies of animals and plants, food sources don't supply recommended dosages.

Therapeutic Dosages

Typical doses recommended by sports supplement manufacturers are 1 to 10 g per day. However, researchers have used much higher doses. For example, in a study focusing on coronary artery disease and exercise-induced ischemia (problems with blood supply to the heart), the participants took 15 grams of ribose 4 times a day for 3 days.2

Typically provided as a powder to be dissolved in water or in liquid form, ribose is also available commercially in capsules. The dissolved powder has a sweetish taste that some people find unpleasant.5

Therapeutic Uses

Ribose may be of benefit in improving exercise tolerance in people with angina by helping the heart regenerate its ATP, but the evidence that it works remains highly preliminary.6 One small study found evidence that ribose supplements might improve heart function in people with congestive heart failure.17

Sports enthusiasts are more interested in ATP's effects on regular muscles than on the heart muscle. At least one animal study seems to show that skeletal muscle, like heart muscle, replenishes ATP more quickly when ribose is added to the blood.7 In theory, this could lead to enhanced performance in high intensity anaerobic exercise, such as sprinting. However, six small double-blind, placebo-controlled trials in humans failed to find any benefit.14-16,18-19,21 In one of these studies, dextrose (a form of ordinary sugar) proved effective while ribose did not.20

In one small, double-blind study, ribose failed to prove effective for enhancing mental function.22 The researchers suggest that the dose they used (2 g daily) may have been insufficient.

In a few case reports, ribose apparently has produced an increase in exercise ability in people with a rare condition involving deficiency of the enzyme myoadenylate deaminase (AMPD).8,9 However, no double-blind studies of ribose in AMPD deficiency have been conducted. Small, double-blind studies have failed to find ribose effective for another rare enzyme deficiency, called McArdle's disease,10 or for Duchenne's muscular dystrophy.11

What Is the Scientific Evidence for Ribose?

Individuals with sufficiently severe coronary artery disease suffer reduced blood flow to the heart (ischemia) with exercise and experience angina pain. One small study examined whether giving ribose can improve exercise tolerance for people with angina.12 In the study, 20 men with severe coronary artery disease walked on a treadmill while researchers noted how long it took for signs of ischemia to develop. For the next 3 days, the men took either oral ribose (60 mg per day) or placebo, after which they repeated the treadmill test. Results of the final test showed that those taking ribose increased the time they were able to walk before developing EKG signs of ischemia, while those taking placebo had no such improvement. This preliminary study was too small to prove anything definitively, but it certainly suggests that further investigation would be worthwhile.

Another small placebo-controlled study enrolled people with coronary artery disease and congestive heart failure and found that use of ribose supplements improved objective measures of heart function and also enhanced subjective "quality of life."17

Safety Issues

There are no reports of lasting or damaging side effects from ribose, but formal safety studies have not yet been conducted. Reported minor side effects include diarrhea, gastrointestinal discomfort, nausea, and headache.13