Subcutaneous Injection: What It Is and How to Give One Injectable L Carnitine: Does It Really Work for Fat Loss? L Carnitine Injections for Fat Loss Benefits & Uses 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 L Carnitine Fat Burning Shotsbecause pictures speak louder than words! These little shots are packed with powerful benefits: Supports weight management Helps reduce body fat Converts fat into energy