Methods: A comprehensive search was conducted across PubMed, Scopus, and Embase up to July 2024
In humans, cyanocobalamin must undergo intracellular enzymatic conversion to the active coenzyme formsmethylcobalamin and adenosylcobalaminwhich, depending on the pH environment, can interconvert with hydroxocobalamin ( Despite extensive biochemical knowledge of cobalamin metabolism and its physiological importance, the optimal supplementation route for maintaining or restoring adequate vitamin B12 levels remains debated
Any failure means discard
Children presenting neurological signs or symptoms, those unable to take oral medication, individuals with known malabsorption syndromes, infants under 6 months old, and patients using medications that may interfere with vitamin B12 absorption are typically treated with a parenteral protocol (1)
If you're 50 or over, your doctor may recommend a B12 shot after a significant blood test