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: Benefits, Side Effects, And Dosage, Per Dietitians Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis Get Rid of Fishy L Carnitine Smell: Essential Fixes Tonum L Carnitine Is it Worth Taking? Ideal Nutrition