Are B12 Injections Safe? Should I Get A B12 Shot? How Long Do the Benefits of Vitamin B12 Injections Last? Are B12 Shots Safe? Royal Palm Beach Medical Group Wow guys, you've been gate keeping!! Got my first B12 injection last week and it's like I am awake for the first time since having kids 20 years ago It's Cyanocobalamin vs Hydroxocobalamin (Vitamin B12 forms) Key Clinical Differences Hydroxocobalamin is preferred in: Pernicious anemia Severe vitamin B12 deficiency Neurological symptoms (subacute combined degeneration, neuropathy) Cyanocobalamin is B12 injections have lots of benefits from just 1 dose. A dose can be given every 6 months to boost benefits, unless you have a b12 deficiency or pernicious anaemia with proof