How does L-Carnitine work to help speed weight loss? What evidence is there that it works?

In a study of 18 overweight subjects, carnitine greatly increased weight loss. The subjects were split into two groups of 9. For 12 weeks, both groups ate a healthy diet and performed moderate exercise. One group was given 2000 mg of carnitine, and the other a placebo. In the placebo group, the average weight loss after 12 weeks was one pound. In the carnitine group, weight loss averaged 11 pounds. That’s an eleven-fold increase in weight loss, simply by increasing carnitine levels. Body fat percentage levels also decreased markedly in the carnitine group.

However, not everyone will experience such a dramatic effect of weight loss with carnitine. In a recent study, individuals taking carnitine for 8 weeks did not experience increased weight loss. So, how does one know if it is even worth trying this supplement. Well, in my experience, individuals following a reduced carbohydrate diet, and incorporating aerobics and strength training, usually find it easier to lose weight while taking carnitine on an empty stomach, 30 minutes before breakfast, when compared to those following the same protocol minus L-carnitine.

We hope all is well with you and that you find this information useful.

Articles of interest:

• Rebouche CJ, Paulson DJ. Carnitine Metabolism and Function in Humans. Ann Rev Nutr 1986; 6:41-66.
• Avogaro P, Bon GB, Cazzolato G, Rorai E. Acute Effects of L-carnitine on FFA and Beta-OH-Butyrate in Man. Pharmacol Res Commun 1981; 13 (5): 443-50.
• Int J Sport Nutr Exerc Metab 2000 Jun;10(2):199-207

Good Luck!

Robert L. Pastore, Ph.D., CNC, CN
Senior Nutritionist at Metabolism.com