L Carnitine is Underrated. New Meta Review Reminds Us Why. Role of Carnitine Shuttle System in the Active Transport of Fatty Acyl Coa into the mitochondrial L Carnitine helps shuttle fatty acids into the mitochondria (the power plants of your cells) where they can be burned for energy. It's often used in fat metabolism and energy support formulas. Nutritional and Hormonal Regulation of Citrate and Carnitine Acylcarnitine Transporters: Two Mitochondrial Carriers Involved in Fatty Acid Metabolism Improving diagnosis of mitochondrial fatty acid oxidation disorders European Journal of Human Genetics