Comprehensive review of the expanding roles of the carnitine pool in metabolic physiology: beyond fatty acid oxidation Journal of Translational Medicine Springer Nature Link Origins and metabolism of trimethylamine in humans Download Scientific Diagram 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 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