Oral will not work, you have to use injectible.
And then, depends which one you have. If it is cyanacobalamin, you have to inject every single day, otherwise it will not work.
If you have hydroxycobalamin, or things like Synthelamin which is cyanacobalamin and hydroxycobalamin stacked, you only have to inject once or twice a week.
When used properly you will get super hungry on it, you will stop bruising if you bruise easily, you will have increased vascularity and you will have a general 'well being' feeling and more energy.