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. Emerging role of trimethylamine N oxide (TMAO) in colorectal cancer Applied Microbiology and Biotechnology Springer Nature Link 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 Intestinal microbiota metabolism of l carnitine, a nutrient in red meat, promotes atherosclerosis Nature Medicine