Exploring the Efficacy of Carnitine as a Dietary Supplement Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum L Carnitine Injection Levocarnitine IV 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. CUD Deficiency Primary Carnitine Deficiency