Compounded Carnitine (L) Injection Empower Pharmacy How to Inject L Carnitine for Weight Loss Safely 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 Subcutaneous Injection: What Is It and How to Give One Ro How to draw up and give yourself a subcutaneous injection