Management of vitamin B12 deficiency is being refined toward simpler, individualized repletion. Parenteral hydroxocobalamin or cyanocobalamin (intramuscular or subcutaneous, with loading doses followed by maintenance) remains standard for malabsorptive causes, but a growing evidence base supports high-dose oral supplementation (around 1000 µg/day) as effective even in pernicious anaemia and malabsorption for many patients — one cohort found the large majority of pernicious-anaemia patients were no longer deficient after a month of oral therapy. Dosing frequency should be individualized, as a substantial proportion of patients need more frequent administration to stay symptom-free, and high-risk groups (ileal disease or resection, and long-term users of metformin or acid suppression) warrant screening.
Further reading: cobalamin deficiency diagnosis and treatment (Wolffenbuttel et al., 2024); oral B12 in pernicious anaemia (Lacombe et al., AJCN 2024); AGA nutritional therapy update (Hashash et al., Gastroenterology 2024).