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 Vitamin B12 Injection Dosage for Adults: 7 Key Facts & Guidelines Liv Hospital What syringe volume and needle gauge and length are appropriate for intramuscular vitamin B12 (cobalamin) injection in an adult, and what is the recommended dosing regimen? B12 Injection Kit: Syringes & Needles & Alcohol Wipes Medbasic How to Give Yourself a Shot GoodRx