What Is Carnitine and Why Is It Important? The Amino Company 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 Therapeutic Uses of L Carnitine: Exploring its Potential Benefits bionova L Carnitine vs L Arginine: Understanding Their Differences and Benefit Fitness Health