iSatori Liquid L Carnitine LS3 3000 Get Rid of Fishy L Carnitine Smell: Essential Fixes Tonum 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, Uses, and Side Effects Lifespan Research Institute A fishy tasting steak is an indicator that your beef is old. As meat breaks down, it can release TMA, a compound responsible for unpleasant, fishy flavors.