Carnitine helps the body convert fat into energy, and is naturally made by the liver and kidneys. L-carnitine is a derivative of lysine, an amino acid found in the body, according to the Linus Pauling Institute at Oregon State University. Supplementation is generally not necessary because most individuals make sufficient amounts of carnitine for health. But supplementation may make sense under certain circumstances.
Select the kind of L-carnitine that is appropriate for you. According to the University of Maryland Medical Center, there are three common kinds: L-carnitine, which is the most widely used and least expensive version; acetyl-L-carnitine, usually used in studies regarding brain disorders and Alzheimer's disease; and propionyl-L-carnitine, used for heart disease and peripheral vascular disease studies. Ask your doctor which kind you should take.
Take 1.5 to 2 grams daily of L-carnitine to treat angina or heart failure; 600 to 1,200 mg three times a day or 750 mg two times a day to help treat heart disease; and take 2 to 4 grams daily for peripheral vascular disease, says the University of Maryland Medical Center. Ask your cardiologist if there are any other precautions you should take while using this supplement.
Consume 3 grams of L-carnitne a day to treat diabetic neuropathy; take 300 to 1,000 mg three times a day for male infertility; 500 to 1,000 mg three to four times a day for chronic fatigue syndrome; and consume 2 to 4 grams daily in two to four doses for an overactive thyroid, suggests the University of Maryland.
Take 500 to 1,000 mg of acetyl-L-carnitine if you are using it for general purposes, recommends the Linus Pauling Institute. Although some individuals may use it to boost athletic performance, no evidence shows that healthy people benefit in this way from the supplement.