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 is an amino acid derivative that plays a crucial role in the bodys energy production processes. As an injectable supplement, L carnitine has been employed to support various health L Carnitine: Intravenous vs. Ingested BodyRejuvenation How L Carnitine Injections Help Boost Fat Metabolism and Energy Levels