Emerging role of trimethylamine N oxide (TMAO) in colorectal cancer Applied Microbiology and Biotechnology Springer Nature Link Stabilizing the enzyme in fish odor syndrome Understanding the Side Effects of L Carnitine Injection and When to Seek Medical Advice Microbiota and MalodorEtiology and Management 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. Trimethylaminuria, or fish odour syndrome is an uncommon condition that causes an unpleasant, fishy smell. The body is unable to turn a strong smelling chemical called trimethylamine produced in the gut when