Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum CARNITINE (L CARNITINE, ACETYLCARNITINE) Neuroneeds Breakthrough in studying the enzyme that ultimately produces fish odor syndrome EurekAlert! L carnitine supplements can cause a fishy odor in the breath, sweat, and urine. This is likely due to the formation of trimethylamine (TMA). TMA is also responsible for the pungent smell of