Well, this is the Iodine supplement forum, so it is our focus.
That said, vit C is definitely part of the regimen most of us take, others too, like vit B, magnesium.
My own kids did relatively well, as myself; until the day thing started to turn the wrong way. All in my history here at the forum. I gave them loads of vitamins, a good diet, but one day it wasnt enough.
Iodine in addition to 4-5 other supplements was needed to correct their / my deficiency.