B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Vitamin B12 Injection at BiosenseClinic.com a Licensed Pharmacy 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. Sandoz Vitamin B12 Injectable Solution 1000 mcg 10 mL Vitamin B12 Cyanocobalamin Vitamin B12 5000 mcg mL, 100 ml Allivet