Carnitine Review

You’ll see carnitine (sometimes written as l-carnitine) in diet pills fairly frequently. This amino acid is “required for transport of fatty acids from the cytosol into the mitochondria during the breakdown of lipids (or fats) for the generation of metabolic energy.” (source: http://en.wikipedia.org/wiki/Carnitine)

When you start talking about breaking down fats into energy, you naturally attract the eyeballs of diet pill manufacturers.

Carnitine Research

One study done on 15 patients (this is a low number) with type II diabetes and 20 healthy volunteers showed an improvement in the disposal of glucose (about 8%). (source: Geltrude Mingrone, Aldo V. Greco, Esmeralda Capristo, Giuseppe Benedetti, Annalisa Giancaterini, Andrea De Gaetano, and Giovanni Gasbarrini (1999). “L-Carnitine Improves Glucose Disposal in Type 2 Diabetic Patients”. Journal of the American College of Nutrition 18 (1): 77-82.)

Carnitine Food Sources

The best place to get carnitine naturally is through red meat. For instance, an ounce of beef steak has 27mg of carnitine. Dairy is also a great source, but whole milk only has about a milligram per ounce. You can see how drastic the concentration is in red meat versus any other source.

So, if you’re big meat eater and someone’s trying to tell you you’re deficient on carnitine…they’re full of it. You’re getting an ample supply!

So is Carnitine effective for Weight Loss?

So far the pickings are slim regarding research supporting that hypothesis. One article published at the University of Maryland Medical Center had this to say:

Although L-carnitine has been marketed as a weight loss supplement, there is no scientific evidence to date to show that it improves weight loss. A recent study of moderately overweight women found that L-carnitine did not significantly alter body weight, body fat, or lean body mass. Based on the results of this one small study, claims that L-carnitine helps reduce weight are not supported at this time.

Another study looked at carnitine as a possible supplement to prevent weight gain in bipolar patients (bipolar patients take a medication called sodium valproate which causes significant weight gain). Sixty biopolar, valproate-treated patients with “clinically significant weight gain” were randomized to take l-carnitine at 15mg/kg/day or a placebo, in conjunction with a “moderately energy-restricted, low-fat diet” for 26 weeks. (Source: Bipolar Disord. 2006 Oct;8(5 Pt 1):503-7.)

Now, keep in mind what their dosage was! For someone my size (78kg) I would need to be taking 1.17g of carnitine (or 1,170mg)!

And what was the result?

At the dose prescribed in this study carnitine supplementation did not improve weight loss outcomes in valproate-treated bipolar patients consuming an energy-restricted, low-fat diet.

Now, it may be that the valproate medication significantly counter-acted carnitine’s effect — or it could also mean that at a 1.2g dose (for an average-sized male) carnitine does not affect weight loss.