Vitamin B12 injections deliver high doses of this essential vitamin directly into your bloodstream for better absorption than oral supplements to boost energy, support red blood cell production and maintain nerve function. I receive monthly intramuscular vitamin B12 (cobalamin) injections, but my serum B12 level measured two weeks after the injection is only 268 pg mL; why is it low and how should the dosing Vitamin B12 Injection Dosage for Adults: 7 Key Medical Guidelines Liv Hospital TREATMENT The B12 Society Compounded Vitamin B Complex Injection Empower Pharmacy Vitamin B12 Injections: Ideal Dosage & Frequency for Men's Health