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 SFI Health Acetyl L Carnitine 90c When to take L carnitine: Dosage, forms, and side effects L Carnitine Injection Kare Pharmacy Injectable L Carnitine for Slimming: Does It Really Work? National Medical Resources Inc