@fly and
@OOD I slightly disagree with both of you but I've had a very important reason to study this for decades, because of an inherited condition. But anyway, my understanding/belief is most people easily get enough regular B12, cyanocobalamin, in their diet. The more usual problem is it's not getting converted to the methyl form, methylcobalamin, which is what your nerves, brain and some other tissue need to do any rebuilding or maintenance of your shit. The conversion occurs in the liver, which is why I made the statement about them giving a B12 shot to alcoholics. SOme responded, those who were too far gone didn't. The state of art method for determining if a conversion issue exists is to do a nerve biopsy since a reliable tblop test for differentiating between the two forms of B12 doesn't exist. .
We've had this convo a number of times since I've came here.