It is currently classified as a research compound and is not approved for therapeutic use in humans in the United States
Vitamin B12 needs Intrinsic Factor : A special protein called intrinsic factor, produced by the stomach lining, rounds up and binds to the freed B12 and once this IF B12 complex travels in the small intestine it attaches to specific receptors in the ileum which triggers absorption into the bloodstream
Mayeda RM, Mobley TM, Weiss RE, Murchland AR, Berkman LF, Sabbath EL
PubMed record Monti JM, Debellis J, Alterwain P, Pellejero T, Monti D
There is still not enough human safety data
Keep unopened vials frozen, reconstitute with bacteriostatic water only when a study calls for it, and refrigerate the reconstituted solution for short-term use