L Carnitine: Benefits, Uses, and Side Effects Lifespan Research Institute L Carnitine injection is recommended at 1 ampule every 2 3 days for best results. The L Carnitine is taken intravenously either by normal injection or using a butterfly needle. After taking this L Carnitine, you Does Carnitine Cause Body Odor? Lume Deodorant 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