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 Levocarnitine Injection: Package Insert Prescribing Info L Carnitine Linus Pauling Institute Oregon State University L Carnitine Injection Levocarnitine IV 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 Injectable vs Oral L Carnitine: Which Works Better? AWP