Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum L Carnitine is Underrated. New Meta Review Reminds Us Why. Liquid L Carnitine 3000 Nutrex Amino Acids Does Carnitine Cause Body Odor? Lume Deodorant What is Carnitine? 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.