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 L Carnitine: Benefits, Side Effects, And Dosage, Per Dietitians Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis CUD Deficiency Primary Carnitine Deficiency L Carnitine Dosage Explained: A Complete Guide The Science of Good Health Acetyl L Carnitine Allergy: Symptoms and Treatment Options (2026) Wyndly