Dr. prescribed B12 injections. Pharmacy only gave me vials. Where do you get your needles and syringes? What size?? Where do I inject? : r B12_Deficiency Choosing the Right Needle and Syringe for B12 Injections: A Complete Guide Treating Severe Vitamin B12 Deficiency B12 IM Injection Vitamin B12 Injections in Tulsa, Oklahoma Emerge B12 vitamin Store Needle and Syringe Information for injecting vitamin B12 and vitamin C. Find out what needle sizes are recommended.