Carnitine: Theraputic Use

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Carnitine is a quaternary ammonium compound biosynthesized from the amino acids lysine and methionine.[1] In living cells, it is required for the transport of fatty acids from the cytosol into the mitochondria during the breakdown of lipids (fats) for the generation of metabolic energy. It is often sold as a nutritional supplement. Carnitine was originally found as a growth factor for mealworms and labeled vitamin Bt. Carnitine exists in two stereoisomers: Its biologically active form is L-carnitine, whereas its enantiomer, D-carnitine, is biologically inactive.[2]
\[edit] Antioxidant effects
The carnitines exert a substantial antioxidant action, thereby providing a protective effect against lipid peroxidation of phospholipid membranes and against oxidative stress induced at the myocardial and endothelial cell level.[9]

[edit] Potential uses as a pharmaceutical
[edit] Heart conditions
Carnitine is primarily used for heart-related conditions. Several clinical trials show that L-carnitine and propionyl-L-carnitine can be used along with conventional treatment for angina to reduce medication needs and improve the ability of those with angina to exercise without chest pain.[10][11] There is little evidence about a positive effect of the use of carnitine after a heart attack. Some studies suggest that people taking L-carnitine may be less likely to suffer a subsequent heart attack or experience chest pain and abnormal heart rhythms.[12] However, other studies have not found similar benefits.[13] Further research on this subject is needed.
[edit] Effects on diabetes
L-Carnitine improved glucose disposal among 15 patients with type II diabetes and 20 healthy volunteers.[14] Glucose storage increased between both groups, but glucose oxidation increased only in the diabetic group. Finally, glucose uptake increased about 8% for both.
[edit] Kidney disease and dialysis
Because kidneys produce carnitine, kidney disease may lead to the deficiency of carnitine in the body. Thus, carnitine may be prescribed to those with kidney disease.[15]
[edit] Effect in male infertility
The use of carnitine showed some promise in a controlled trial in selected cases of male infertility by improving sperm quality.[16] L-carnitine supplementation has also shown to have beneficial effects in the treatment of varicocele, a major cause of male infertility. [17]
[edit] As a weight loss supplement
"Although L-carnitine has been marketed as a weight-loss supplement, there is no scientific evidence to show that it improves weight loss; however, some studies show that oral carnitine reduces fat mass, increases muscle mass, and reduces fatigue. All of these effects may contribute to weight loss." [18]
Regular supplements of L-carnitine, however, contribute to energy metabolism and improved neurotransmitter function in the brain in elderly patients.[19]
[edit] As an antidote in valproic acid poisoning
"[In the treatment of valproate toxicity] L-carnitine supplementation ...is thought to provide benefit, particularly in patients with concomitant hyperammonemia, encephalopathy, and/or hepatotoxicity."[20] Further trials are warranted, as benefit is largely theoretical, rather than proven at this stage.
[edit] Sources