Patient with significantly low serum B2 tried taking methylcobalamin orally for two months diligently, and B12 levels didn’t budge. Each meeting has a clinical presentation of hypochlorhydria, very gluten intolerant. Should she take sublingual B12 or get an intramuscular injection?

Chris: Good question. In studies that have been done recently, sublingual B12 has been shown to be equivalent to intramuscular in terms of raising B12 levels, but I think in some cases, there are just certain patients who do better with injections, and injections can raise B12 levels faster than sublingual. In a situation like this, you might consider starting with a couple of B12 injections and then transitioning the patient to sublingual over the long term. That’s generally much more convenient as a way of maintaining normal B12 levels, but the injections could be helpful in terms of getting her into that normal range more quickly.