Vitamin B12 Injections: Benefits and Risks Where does vitamin B12 come from? And why is it so hard to produce? Vitamin B12 Food Sources and Why Take Vitamin B12 Supplements People love to bring up B12 like it's a reason to eat meat. But here's the irony Even meat eaters can be deficient in B12. That's because B12 comes from bacteria in The B12 Shot: What Every Human Needs to Know About Injectable Vitamin B12 Vitamin B12 Injections: What You Need To Know