TMAO: how gut microbiota contributes to heart failure Translational Research L Carnitine Linus Pauling Institute Oregon State University 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. Fluoromethylcarnitine, a novel inhibitor of trimethylamine levels in trimethylaminuria and trimethylamine N oxide related disorders ScienceDirect Treatments of trimethylaminuria: where we are and where we might be heading ScienceDirect L Carnitine: Everything You Need to Know