Naturliders Liquid L-Carnitine with Synephrine is a nutritional supplement used in sports nutrition. L-Carnitine is an amino acid that helps transport fatty acids to cells to be used as an energy source during physical exercise. Synephrine is a compound that stimulates metabolism and fat burning. This product is used to improve athletic performance, increase fat burning, and promote weight loss. Ingredients The main active ingredient in this product is L-Carnitine.