11 Urine Smells Explained In Everyday Life Some food and drink habits show up in a very ordinary place, and people are always a little surprised by how fast it happens. A L Carnitine Injection Levocarnitine IV L Carnitine Liquid 1500 Heat Thermogenic Stabilizing the enzyme in fish odor syndrome 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. 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.