Thanks Grizz, I used to give her 2000-3000iu of D3 daily but didn't make any difference so now I have stopped, sometimes I do feel like I give my kids so many supplements. Perhaps the D3 was doing some good but I couldn't see any results. Although I understand that magnesium plays a big part and I think she is deficient so this could have something to do with it. She is now having magnesium as part of the Iodine so-supplements. That last link you posted to hypothyroid symptoms is one of the most comprehensive I've seen though - didn't realise frequent infections and sinus probs etc were a hypothyroid symptom. Maybe I just do need to increase her Iodine intake and stick with it. Thanks for advice. :-)