VITAMIN B12 INJECTION 1000 mcg mL Cyanocobalamin (B12) Injection 1000 mcg mL, Multiple Dose Vial 30 mL McGuff 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. CYANOCOBALAMIN INJECTION, USP 30000 mcg 30 mL (1000 mcg mL) 30 mL VIAL A little insight to the importance of the b12 injections. My client hadn't been feeling well & had some bloods done with her GP. The results identified a severe deficiency in b12.