Vitamin B12 Injections in Appleton Gameday Men's Health Flyer B12 Injection RxConnexion How to Give B12 Injections at Home to Yourself PA Relief Still injecting in the same spot every time? Read this. Where you inject your peptides can actually affect absorption, comfort, and results. Quick guide: Abdomen: fastest absorption Upper arms Best Vitamin B12 Injection Sites: Where to Inject B12 PA Relief B12 vitamin Store How to Perform a Subcutaneous Injection of Vitamin B12