Method Absorption Rate Advantages Disadvantages Oral pills 1.2-40% depending on intrinsic factor Convenient, widely available Poor absorption, especially with age or GI issues Sublingual Slightly better than pills No need for intrinsic factor, easy to use Still less effective than injectable forms In-clinic IM injection Nearly 100% Highly effective, professionally administered Requires clinic visits, potential travel and waiting time At home B12 injection Nearly 100% Highly effective, convenient, no travel needed Requires training, prescription, and comfort with self-injection IV infusion 100% Immediate delivery to bloodstream Most expensive, requires professional administration For many people especially those with serious deficiencies, digestive disorders, or pernicious anemia at home B12 injection offers the sweet spot of effectiveness and convenience
Vitamin B12 deficiency may affect between 1.5 to 15 percent of people
(More information) Other Articles Vitamin B 12 has the largest and most complex chemical structure of all the vitamins
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Lead author, Dr Natasha Tyler said: Patients with vitamin B12 deficiency often report feeling marginalised and describe their interactions with primary care as battles and report feeling stigmatised
Research has explored its effects on adipose tissue, body composition, and metabolic rate regulation
