L CARNITINE INJECTION Intramuscular vs. Subcutaneous Injections: What's the Difference? Intramuscular (IM) shots go deep into the muscle for faster absorption, while subcutaneous (SubQ) injections are placed just under the skin for slower, more sustained How to Inject L Carnitine for Weight Loss Safely Subcutaneous Injection: What It Is and How to Give One How to Self Administer Subcutaneous & Intramuscular Injections