Carnitine: Health Benefits, Supplement Uses, Side Effects, Daily Intake 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. Unlocking the Health Benefits of L Carnitine and Potential Side Effects Your Health Magazine 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 Male Enhancement: What the Evidence Shows for Energy, Sperm Health, and Performance