L Carnitine Linus Pauling Institute Oregon State University JCI l Carnitine in omnivorous diets induces an atherogenic gut microbial pathway in humans 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 Pharmacokinetics of L Carnitine : Clinical Pharmacokinetics