Best Vitamin B12 Injection Sites: Where to Inject B12 PA Relief Lets do my first B12 injection together This is something Ive been nervous about for a long time, but today I finally did itand it honestly wasnt bad at all. I used the Union Medico needle guide Pernicious Anemia (Rare Cause of Vitamin B12 Deficiency) Causes, Symptoms, Diagnosis, Treatment The B12 Shot: What Every Human Needs to Know About Injectable Vitamin B12