Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum 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 Is fish smelly? If you have ever caught fresh fish, you know that it doesn't have a particularly strong odor, maybe a hint of ocean water. But when fish are killed, bacteria