L Carnitine Benefits for Fat Burning and How to Use ICONFIT 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 Revisiting the Role of Carnitine in Heart Disease Through the Lens of the Gut Microbiota Benefits of L Carnitine:, When taken as a supplement, L Carnitine has been shown to have a beneficial impact on weight loss and improved brain function. It has also been linked to improved heart