Learn how to administer your own SubQ (subcutaneous) injections at home with confidence. Our step by step guide covers everything you need to know, from preparing your supplies to safely injecting the medication. Our Common IM Injection Sites Deltoid (Upper Arm) Location: About 23 finger widths below the acromion process (shoulder bone). Best for: Vaccines and small volume injections (1 mL). Notes: Easy to access but limited Vitamin B12 Injections B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics B12 Injections at Home Safety Guide for Self Administration Infusion For Health