How Vitamin B12 Injection Dosage and Frequency Influence Weight Loss AlabamaAgeline.gov Oral vs. Intramuscular Vitamin B12 in Vitamin B12 Deficiency The Blood Project Vitamin B12 Injection Dose for Weight Loss: What Does the Science Say? AlabamaAgeline.gov B 12 Shot Happy Hour Synergy Natural Medicine Clinic 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. Cyanocobalamin (B12) Injection 1000 mcg mL, Multiple Dose Vial 30 mL McGuff