Vitamin B 12 Injection, 5,000 mcg mL, 100 ml Vitamin B12 Injections: What You Need To Know New Service Launch** We will now be offering Vitamin B12 depot injections for anyone interested for their health and wellbeing. Some of the benefits of having a Vitamin B12 injection are; Vitamin B 12 Injection for Animals, 3000 mcg mL, 100 mL Vial Prescription Medication for Pets 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.