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 Carnitine Rich Foods: Understanding L Carnitine and Its Benefits Loyal Does Carnitine Cause Body Odor? Lume Deodorant L Carnitine: Benefits, Uses, and Side Effects Lifespan Research Institute Frontline L Carnitine Fit Factory Supplements