Does Carnitine Cause Body Odor? Lume Deodorant Trimethylamine Wikipedia 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. The effect of l carnitine supplementation on mortality and clinical outcomes in ventilator dependent critically ill patients with obesity and COVID 19: Protocol for a randomized double blind placebo controlled trial ScienceDirect Full article: Trimethylamine N oxide formation, the bacterial taxa involved and intervention strategies to reduce its concentration in the human body