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 What's the Difference Between CLA and Carnitine? L Carnitine for Erectile Dysfunction: What the Evidence Shows and How to Use It L Carnitine: Benefits, Risks, and Its Role in Fitness and Weight Loss WellnessPulse L Carnitine: Benefits, Side Effects, And Dosage, Per Dietitians