Trimethylamine N Oxide From Gut Microbiota in Chronic Kidney Disease Patients: Focus on Diet Journal of Renal Nutrition 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. 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 Human model of primary carnitine deficiency cardiomyopathy reveals ferroptosis as a novel mechanism: Stem Cell Reports