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 VITAMIN B12 INJECTION 1000 mcg mL B12 vitamin Store Intramuscular vs Subcutaneous Injections for vitamin B12 supplements. B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics What Happens If You Inject B12 Wrong: 6 Red Flags Dr. prescribed B12 injections. Pharmacy only gave me vials. Where do you get your needles and syringes? What size?? Where do I inject? : r B12_Deficiency