Have you any research to prove that the supplements won't be absorbed please ?Often B12 deficiency is caused by the inability to absorb Vit B12 from foods, if that is the reason the oral vit B12 will not help and injections of B12 would be required usually 3 monthly.
Absorption of vit B12 requires intrinsic factor which is prevented from being produced by some medications or gastric conditions.Have you any research to prove that the supplements won't be absorbed please ?
Carol