CUD Deficiency Primary Carnitine Deficiency L Carnitine L Tartrate Powder True Protein L Carnitine: Benefits, Uses, Side Effects, and More Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis 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 Side Effects & Safety: A Complete Guide The Science of Good Health