Breakthrough in studying the enzyme that ultimately produces fish odor syndrome EurekAlert! 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. Stabilizing the enzyme in fish odor syndrome Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum Any advice for fishy smell with L carnitine?