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 Propionyl L carnitine for erectile dysfunction Does L carnitine cause fishy body odor? Surprising Truth and Solutions Tonum Veterinary Strength Healthy Heart for Dogs & Cats Acetyl L Carnitine Alpha Lipoic Acid Erectile Dysfunction: What the Evidence Shows and Practical Considerations