Why do some elderly take B12 sublingually or transdermally? Provide a detailed answer with research to back it up. Cite your source. Solution The oral route of administration of vitamin -B12 (cynacobalamin) has poor absorption rates in older senior citizens during the treatment of pernicious anemia whereas intramuscular route of administration is going to cause severe pain finally inflammation or wound, which is likely take longer time to heal (if they have diabetes). So that it is essential to provide them sublingual tablets or transdermal B12 patches to provide them a better absorption into direct \"blood transport\". This is because sublingual route has associated with direct exposure of blood capillaries so that promotes easy absorption.