Palmitoyl-L-carnitine-13C3 Hydrochloride is carbon-13 labeled Palmitoyl-L-carnitine Hydrochloride (P155050), a long-chain fatty ester of carnitine which is accumulated and released into the circulation, in fatty-acid oxidation defects. Pattern of Lauroyl-L-carnitine can be diagnostic for a number of ß-oxidation defects.