100% Pure L Carnitine by Genetix Nutrition Essentials Nutrition Warehouse Trimethylaminuria (Fish Odor Syndrome or TMAU) Injectable L Carnitine: Does It Really Work for Fat Loss? Fish Odor Carnitine TikTok 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.