Choosing the right needle is about matching the gauge and length to the specific task, whether it's a quick vaccination or drawing blood. Here is a simplified breakdown of the most common needles used like, swipe, and save for when it's your turn to do an injection on a patient Intramuscular (IM) Angle: 90 Needle Size: 2225G, 11.5 inch Med Examples: Vaccines (e.g. Tdap, How to draw up Lipotropic (labeled as MIC B12) Injections Transformations Weight Loss B12 vitamin Store Needle and Syringe Information for injecting vitamin B12 and vitamin C. Find out what needle sizes are recommended. How to self inject intramuscular vitamin B12 Overview Guy's and St Thomas' NHS Foundation Trust