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 12 Urine Smells What Do They Really Mean? Your urine can tell you a lot about what's happening inside your body. Changes in smell are often harmless, but sometimes L Carnitine Injection Levocarnitine IV TMAU: Diet to reduce a fishy odour Dietitian's Life Stabilizing the enzyme in fish odor syndrome