Originally Posted by mrsD

It is hard to say. If all the B12 is cyano form... and you could not methylate it (activate it), it wouldn't do much for you then.

The MMA test would show if the B12 you have is working.
If your MMA is a very low number, then you could say, you don't need it.

If your serum level of B12 is high only because you are continuing to take it, (not stopping it 3 to 7 days before testing), then you don't know what it would be if you did stop it.

There are some medical conditions that can raise B12 levels without any supplements being taken. Kidney problems, some cancers, and intestinal overgrowth of some GI organisms are
possible, and some liver issues.