Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum L Carnitine injection is recommended at 1 ampule every 2 3 days for best results. The L Carnitine is taken intravenously either by normal injection or using a butterfly needle. After taking this L Carnitine, you Stinky People, Odor Sensitivities & Ammonia Toxicity FUNCTIONAL MEDICINE, SIBO & IBS DR HOUSTON ANDERSON Does Carnitine Cause Body Odor? Lume Deodorant Trimethylaminuria (Fish Odor Syndrome or TMAU) 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.