If you are like a lot of people, you may have never heard of carnitine but this important nutrient is critical for our body's ability to optimally burn fat required for energy. Get Rid of Fishy L Carnitine Smell: Essential Fixes 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 Did You Know? Some people report a fishy smell after supplementing with L carnitine. This happens because certain gut bacteria convert carnitine to trimethylamine, a malodorous compound found in rotting fish. Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum Gut Derived Metabolite, Trimethylamine N oxide (TMAO) in Cardio Metabolic Diseases: Detection, Mechanism, and Potential Therapeutics