Cyanocobalamin (B12) Injection 1000 mcg mL, Multiple Dose Vial 30 mL McGuff What Happens If You Inject B12 Wrong: 6 Red Flags Vitamin B 12 intramuscular injections are also used therapeutically to help restore energy and combat various symptoms related to such deficiencies. Vitamin B 12 is essential to the development of healthy blood cells, nerve B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics