L Carnitine L Tartrate Powder True Protein Acetyl L Carnitine: Benefits and Side Effects Gene Food A recurring fishy odor could indicate a larger medical problem. 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 Get Rid of Fishy L Carnitine Smell: Essential Fixes Tonum