Vitamin B12 Injection: Energy Boost and Anemia Treatment Mountainside Medical Cyanocobalamin is the preferred supplemental form of vitamin B 12 as there is insufficient evidence to support the efficacy of the other forms like methylcobalamin. Michael Greger MD, How Not to Die. B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Vitamin B12 Injection Dose for Adults: 7 Key Facts on Dosage & Frequency Liv Hospital