Several factors can impair B12 absorption: Reduced stomach acid production (achlorhydria or hypochlorhydria), common in older adults and those taking proton pump inhibitors or H2-receptor antagonists long-term, impairs the release of B12 from food proteins Pernicious anaemia , an autoimmune condition destroying parietal cells and reducing intrinsic factor production, completely blocks the primary absorption pathway Gastrointestinal disorders including Crohn's disease, coeliac disease, or surgical removal of stomach or ileum sections directly damage absorption sites Metformin , commonly prescribed for type 2 diabetes, may reduce B12 absorption through unclear mechanisms
Alongside B12, a full blood count, folate level, and consideration of other causes (such as thyroid function and coeliac disease screening) may be appropriate
Intramuscular injections bypass the digestive system to get the vitamins where they belong, for serious results
Pregnant or breastfeeding women should consult their physician before use
Normal Dose of B12 Injection for Adults, Dose for Maintenance Therapy The normal dose of B12 injection for adults is key in managing Vitamin B12 deficiency
