Should You Take Natural vs. Synthetic B12? Compounded Cyanocobalamin (Vitamin B12) Injection Empower Cyanocobalamin (B12) Injection 1000 mcg mL, Multiple Dose Vial 30 mL McGuff Cyanocobalamin Injection: Vitamin B12 Deficiency Relief Mountainside Medical NEW TREATMENT ALERT A vitamin B12 injection helps treat or prevent deficiency by delivering the vitamin directly into the bloodstream. It's often used for people with absorption issues and is usually safe