Blood tests and other diagnostic measures can help identify specific deficiencies or conditions the injections could address
Folate: correcting folate alone can mask B12 deficiency and risk neurologic harmcheck both if anemia is present (NHS)
The synthetic form, cyanocobalamin, is the form most commonly used in supplements and foods, as it is cheap to produce
The liver stores are a bit irrelevant to someone who has PA or a B12 absorption problem though because the mechanism that is used to release them relies on the same mechanism that is used to absorb most dietary B12 so accessing any stores is at best very inefficient
Cox, Daniel Eichner Published: Drug Testing and Analysis, Volume 7, Issue 1, January 2015, pages 3138 DOI: 10.1002/dta.1715 URL: AOD9604 was incubated in human serum and rat plasma at room temperature to study in vitro metabolic degradation