B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Types of injections explained Intramuscular (IM) Inserted at 90 to deliver medication deep into the muscle, allowing relatively fast absorption due to rich blood supply. Subcutaneous (SC) Inserted at about 45 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) : Oral vs. Intramuscular Vitamin B12 in Vitamin B12 Deficiency The Blood Project