Vitamin B12 Injections: Benefits and Risks Vitamin B12 deficiency, sometimes called cobalamin deficiency, happens when your body is either not getting enough or not absorbing enough vitamin B12 from the foods you eat. Vitamin B12 is an important Best B12 Shots in Chicago & Naperville 2026 Fun Fact Friday! Ever wondered Why is my B12 injection red? All B12s are cobalamins they have a cobalt atom at the center of a special ring shaped molecule called