When to take L carnitine: Dosage, forms, and side effects 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 Maximum L Carnitine Alfa Vitamins Alfa Vitamins Store Best Time to Take L Carnitine: A Complete Guide The Science of Good Health L Carnitine with Apple Cider Vinegar EC Sports Supplements