This medication is a diet supplement used to prevent and treat low blood levels of carnitine. Carnitine is a substance made in the body from meat and dairy products. It helps the body use certain chemicals (long-chain fatty acids) for energy and to keep you in good health. Low blood levels of carnitine may occur in people whose bodies cannot properly use carnitine from their diets, people on dialysis due to serious kidney disease, and people being treated with certain drugs (e.g., valproic acid, zidovudine). Carnitine levels that are too low can cause liver, heart, and muscle problems.