I've just been diagnosed with Hashimotos by a private GP having got nowhere with the NHS and before seeing her I had started to supplement my B12 as it was down to 290 (211-900).
My GP said that was perfectly ok but I was having really bad headaches, memory loss and occasional pins and needles in my fingers so I took 5000 mcg sublingually per day plus another 1,500 from a b complex. My latest result is 1411 (300-835) so I think I'll reduce it now!
The doctor who diagnosed me said it is likely I have PA as I my condition is autoimmune but if that was the case surely my B12 wouldn't have risen as it has? I should mention my father has Crohn's disease and also PA. I don't know if it's relevant but my MCV before supplementing was 96fl (83-101) and after it was 96fl (80-95), sorry about the different reference ranges.
Any thoughts or advice would be most welcome.