L Carnitine Force Factor 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 Amazon.com: Force Factor L Carnitine Liquid 3000mg, Maximum Strength Supplement to Support Fat Metabolism, Cellular Energy & Muscle Recovery, High Absorbing, Non GMO, Orange Flavor, 16 oz Bottle : Health & Household L Carnitine 3000 Liquid Essential L Carnitine Optimal Health Systems L CARNITINE 350 MG ( L CARNITINE ) 20 HARD GELATIN CAPSULES