Acetyl-l-carnitine is an amino acid which has a role to play in the body's fat metabolism process. L-Carnitine transports fatty acids to the mitochondria, which is where they are essentially burned as fuel. This amino acid naturally occurs, although it can also be biosynthesized from two other ones. In addition to being found in a wide range of foods, it is also commonly available as a dietary supplement.
To date, few clinical trials have tested l-carnitine's effectiveness as a weight loss aid.The available research includes a 2000 study from the International Journal of Sport Nutrition and Exercise Metabolism, in which 36 moderately overweight premenopausal women were given either L-carnitineor a placebo twice daily for eight weeks. Analyzing study results, researchers found no difference in total body mass or fat mass between those who took L-carnitine and those given the placebo.A number of animal studies have also shown that L-carnitine may not support weight loss. A 2002 study from the Annals of Nutrition and Metabolism, for instance, found that rats treated with l-carnitine did not experience a greater reduction in body fat levels compared to a control group.What's more, a 2005 study published in theInternational Journal for Vitamin and Nutrition Research found that rats fed an L-carnitine-enhanced diet tended to gain more weight than other animals in the study (despite no difference in their intake of calories).
Caveats
In some cases, L-carnitine supplements may produce certain side effects (including nausea, abdominal cramps, diarrhea, and a "fishy" body odor).In addition, L-carnitine may interact with antibiotics used in the long-term prevention of urinary tract infections (such as pivampicillin).
