Vitamin B12 Dosages: Your GoodRx Guide GoodRx 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. VITAMIN B12 INJECTION 1000 mcg mL Oral vs. Intramuscular Vitamin B12 in Vitamin B12 Deficiency The Blood Project At Home Vitamin B12 4 Week Injection Package MUST BE A FLORIDA RESID CardioMender, MD Cyanocobalamin (B12) Products American Regent