Hi Dr. Tony here! If you give yourself injectionstestosterone, estrogen, insulin, peptides, or B12these are 3 of my favorite tips to make them almost painless. Tip 1: Insert the needle quickly, then Where to Inject Vitamin B12 Do You Need a Prescription for B12 Injections? OmegaQuant How to Self Administer Subcutaneous & Intramuscular Injections Treating Severe Vitamin B12 Deficiency B12 IM Injection How To Give Yourself Vitamin B12 Shots (with video!)