Ever heard of Fish Odor Syndrome? Its a rare condition where the body cant break down trimethylamine a compound found in foods like fish, eggs, and beans. This leads to a strong, fish like smell 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 L carnitine supplements can cause a fishy odor in the breath, sweat, and urine. This is likely due to the formation of trimethylamine (TMA). TMA is also responsible for the pungent smell of L Carnitine Side Effects & Safety: A Complete Guide The Science of Good Health Potential Adverse Effects of L Carnitine Marnys