Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum 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 L Carnitine in the Treatment of Psychiatric and Neurological Manifestations: A Systematic Review L CARNITINE 1 GM 5 ML ( L CARNITINE ) 5 X 5 ML IV USE AMPOULES