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 Know Your Needles A Quick Nursing Guide! , Today, lets understand the different types of needles and their clinical purposes , Green Needle (21G) For IM injections like vaccines or B12 Shots Richardson Weight Loss Richardson Vitamin B12 Injections If youre still guessing needle sizes were not doing that in 2026 , Heres what you MUST know:, Smaller gauge number = BIGGER needle, 1820G = blood & trauma, 2123G = IM, 2527G = How to draw up Lipotropic (labeled as MIC B12) Injections Transformations Weight Loss