How To Self Inject B12 B12 vitamin Store Intramuscular vs Subcutaneous Injections for vitamin B12 supplements. How to Give a B12 Injection: Step By Step Instructions Subcutaneous (SC) and Intramuscular (IM) Injections Must Knows for Subcutaneous administration: Pinch skin with non dominant hand and hold syringe with dominant hand Always inject: 2 inches away from umbilicus (for abdomen) 3 inches How to Self Inject Vitamin B12 at Home The Sanctuary Wellness Institute