How to self inject intramuscular vitamin B12 Overview Guy's and St Thomas' NHS Foundation Trust Not all shots are the same here's a guide Injections are a fast, effective way to deliver medications, nutrients, and vaccines directly into the bodybut not all injections are the Best Vitamin B12 Injections Dosage And Frequency PA Relief B12 Methylcobalamin B12 Injection 1500mcg Vitamin B12 Injection Vita B12 Injection 1mg ml 3 Ampoules Vitamin B 12 Cyanocobalamin 1,000 mcg mL Intramuscular or Subcutaneous Injection Multiple Dose Vial 30 mL