Vitamin B12 Shots Aesthetics Julie Edwards for B12 Shots in Lytham How to Give B12 Injections at Home to Yourself PA Relief How Long Does It Take Vitamin B12 Injections to Work? Gym goers spending monthly on vitamin B and C injections Have a f*cking word with yourself. Both are water soluble, so don't stick around for long in your system (12 14hrs) hence How often should vitamin B12 injections be administered and how frequently should laboratory monitoring be performed? B12 Injections: How Often Should You Take Them? Invigor Medical