L Carnitine Injection (Intramuscular): How It Works & What to Expect Mesotherapy Cocktails, Exosomes Regenerative Skin Boosters 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 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, USP1 g per 5 mL vial and 4 g per 20 mL vialFOR INTRAVENOUS USE ONLYRx Only L Carnitine Intramuscular shot ELIXR IV Therapy