How to self inject intramuscular vitamin B12 Overview Guy's and St Thomas' NHS Foundation Trust Desensitization for Vitamin B12 Hypersensitivity and How to Do It B12 Shots vs. IV Infusions: What is the difference? Integrative Medicine, Laser and Aesthetics Standard Guideline Template TYPES OF INJECTIONS, Injections are parenteral routes of drug administration used when rapid action is required, oral route is not feasible, or precise dosing is needed., 1. Intradermal (ID)