Trimethylaminuria (Fish Odor Syndrome or TMAU) Over 90% of your body's energy comes from mitochondria. When they break down, everything else does too. Think: Fatigue that sleep doesn't fix Brain fog and memory issues Slow Does Carnitine Cause Body Odor? Lume Deodorant 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.