B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Types of injections explained! Understanding the angles: intramuscular (im) : injects deep into the muscle at 90. subcutaneous (sc) : goes under the skin at 45. intravenous (iv) : How to Give a B12 Injection: Step By Step Instructions How to Self Inject Vitamin B12 at Home The Sanctuary Wellness Institute Vitamin B12 Injection IV or IM