How to self inject intramuscular vitamin B12 Overview Guy's and St Thomas' NHS Foundation Trust Ulove Prs 12 Pack 1ml Industrial Syringes with 25Ga 1 Inch Needle, Plastic Disposable Syringe and needle for Scientific Labs, Liquids Refilling and Measuring : Industrial & Scientific Amazon.com Not all shots are the same here's a guide Injections are a fast, effective way to deliver medications, nutrients, and vaccines directly into the bodybut not all injections are the B12 vitamin Store Needle and Syringe Information for injecting vitamin B12 and vitamin C. Find out what needle sizes are recommended.