Acetyl L carnitine erectile dysfunction: What the evidence and real world use actually show Trimethylamine and Trimethylamine N Oxide, a Flavin Containing Monooxygenase 3 (FMO3) Mediated Host Microbiome Metabolic Axis Implicated in Health and Disease Drug Metabolism and Disposition Frontiers Role of Carnitine in Non alcoholic Fatty Liver Disease and Other Related Diseases: An Update 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.