Because of this, the most effective forms of B12 supplementation, aside from dietary sources, are either sublingual supplementation or vitamin B12 injection.
If a particular vitamin is manufactured in tablet form, it may not be as readily absorbed into the system as a liquid or sublingual formula.
Sublingual vitamins are typically placed under the tongue and are absorbed directly through the skin and into the blood stream.
Source Naturals Sublingual B12--For those with problems absorbing B12, a sublingual form is recommended.
In these cases, you can purchase a sublingual form of the vitamin for better absorption.