L Carnitine Injections Nuceria Health, Miami, FL L Carnitine Injections: A Clinical Guide for Practitioners National Medical Resources Inc 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 Are some methods of administering HRT inherently better than others? Audience requested: subcutaneous injections. Subcutaneous means under the skin. In this type of injection, a short needle is used to inject medication L CARNITINE doses seen most say 600mg per day that cost would add up fast is that the basic dose if it's an injection