Research supports both oral and injectable administration
Even the pharmaceutical advertising, with images of healthy people living active lives, uses nearly identical visual language for both drug classes
J Clin Endocrinol Metab 100(3):E453E457 Imam SK (2016) White adipose tissue: beyond fat storage
Todd, at the University of Cambridge, used the LLD assay to extract the anti-pernicious anemia factor from liver extracts, purify it, and name it vitamin B 12
But it does require a different approach
Some are produced by the body by processing food, others, which the body cannot synthesize, must be taken directly with food