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 Syringes and Needles Medical Syringes Luer Lock Needle Sizes Explained: Choosing the Right Gauge for Different Injections Self injecting vitamin B12. Quick and painless jabs after a B12 by Dr Caroline Palmer Medium How to self inject intramuscular vitamin B12 Overview Guy's and St Thomas' NHS Foundation Trust