Robust, randomised, placebo-controlled human trials are essentially absent for both peptides
I'm going to give you this
This is especially true in people who don't consume animal flesh who are also either pregnant or lactating, per Harvard's School of Public Health and Village Pharmacy of Hampstead
The guidelines state, However, pernicious anaemia in its true sense (that is, life-threatening anaemia) is now extremely rare because of developments in testing and treatment for, and greater awareness of, vitamin B 12 deficiency . In one sense, this statement is correct: the term pernicious anaemia, when taken literally, implies a severe, life-threatening form of anaemia, which is uncommon in modern practice due to improvements in testing and treatment, such severe manifestations are typically prevented, as the condition is more likely to be diagnosed earlier or treated with B 12
And the doctor who prescribed it would refute the lack of data, saying the absence of evidence is not evidence of absence, and that his patients are deriving substantial benefit without side effects
A 0.25mg starting dose at that concentration is 2.5 units at the edge of insulin-syringe measurement accuracy