b12 injection im vs sq How to self-inject intramuscular vitamin - Overview B12 Shots vs. IV Infusions:

dose absorption ratio Cyanocobalamin requires conversion to metabolically active cobalamin

And since the nutrient is water soluble, you cant take in too much

Dosage Schedule: The treatment usually starts with an intensive phase (e.g., daily or every other day) to replenish stores, followed by a less frequent maintenance phase (e.g., once a month or once every few months)

The larger the volume of a shot, the more pressure effect/tissue stretching effect that may occur and in a sensitive child cause a feeling of discomfort

Adverse reactions reported following methylcobalamin administration include headache, infection, nausea/vomiting, paresthesias, and rhinitis

The flexibility of these preparations lets doctors adjust the dose as needed