I would take at least 1000 mcg all at once. I would take the cyanocobalamin until able to get the methylcobalamin, and then switch entirely to methylcobalamin. Then, after a while on the methylcobalamin, if she wants to use up the cyano, fine.

Could use a combo of the two. The methylcobalamin right away would just cover some of the rarer reasons she might benefit more from that form.

Timed release is a very bad idea because if she malabsorbs severely she will get nothing from it. And even if she doesn't malabsorb severely now, it could be worsening and move to that, in which case she would get less and less, until eventually zero.

Yes, B12 deficiency can cause those things. It affects individuals in many different ways, and those are on the very long list of possibilities.

rose