The Benefits of Supplementing Your Diet with L Carnitine Challenger Nutrition 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 Natural Fitness Support NOW Supplements L Carnitine, 500 mg, 30 Vegetarian Capsules L Carnitine: Unveiling the Science Behind its Role in Effective Weight Loss Aesthetics 360 Lash & MedSpa L Carnitine Force Factor