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Injections : Vitamin B12 injections, particularly hydroxocobalamin, can be administered under medical supervision to bypass the digestive system and minimise allergic reactions
Red Blood Cells Formation: Vitamin B12 is vital for developing red blood cells
Cyanocobalamin is indicated for vitamin B12 deficiencies due to malabsorption which may be associated with the following conditions: Addisonian (pernicious) anemia Gastrointestinal pathology, dysfunction, or surgery, including gluten enteropathy or sprue, small bowel bacteria overgrowth, total or partial gastrectomy Fish tapeworm infestation Malignancy of pancreas or bowel Folic acid deficiency It may be possible to treat the underlying disease by surgical correction of anatomic lesions leading to small bowel bacterial overgrowth, expulsion of fish tapeworm, discontinuation of drugs leading to vitamin malabsorption (see PRECAUTIONS-Drug Interactions), use of a gluten-free diet in nontropical sprue, or administration of antibiotics in tropical sprue
Hill, 2013
For example: Gastric Sleeve and Gastric Bypass: 500 mcg per day is typically advised