Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum Acetyl L Carnitine: Benefits and Side Effects Gene Food 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: Benefits, side effects, and dosage L Carnitine: Everything You Need to Know The Role of l Carnitine in Mitochondria, Prevention of Metabolic Inflexibility and Disease Initiation