Vitamin B 12 Injection Mobile and Clinic IV Therapy ASAP IVs IV Hydration Experts of San Diego, Phoenix, Scottsdale, San Francisco How Long Does a B12 Shot Last? Duration, Benefits & Timing CYANOCOBALAMIN INJECTION, USP 30000 mcg 30 mL (1000 mcg mL) 30 mL VIAL Vitamin B12 Deficiency: Vitamin B12 deficiency is a nutritional or absorption related disorder leading to impaired DNA synthesis and neurologic dysfunction, commonly presenting with megaloblastic anemia and neuropsychiatric symptoms. Physiological