Does Carnitine Cause Body Odor? Lume Deodorant Liquid L Carnitine 3000 Nutrex Amino Acids 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. 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 is Underrated. New Meta Review Reminds Us Why.