Chronic L-Carnitine L-Tartrate Supplementation Increases Exercise Induced Carbohydrate Oxidation in Men

Figure 1: Molecular structure of
L-Carnitine (HMBD v2.5)

Carnitine supplementation is commonly advertised as a means to shift substrate metabolism from carbohydrate to fat. A new study by Abramowicz and  Galloway indicates that - at least for L-Carnitine L-Tartrate (LCLT) - the opposite is the case.

Carbohydrate oxidation was significantly increased in following chronic supplementation 93.8 g/hr vs. placebo 78. This shift in substrate metabolism was not observed in the female subjects, though.

From a more general perspective the result that

"No effects on fat oxidation or hematological responses were noted in either gender group."

may well be of greater importance to the average gym-rat tempted to invest his hard-earned money into colorfully marketed carnitine products.