Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum 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. L Carnitine Pills for Weight Loss: Evidence, Safety and UK Guidance Bolt Pharmacy Trimethylamine N Oxide in Aquatic Foods Journal of Agricultural and Food Chemistry Trimethylamine N Oxide From Gut Microbiota in Chronic Kidney Disease Patients: Focus on Diet Journal of Renal Nutrition 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