I take HC. I was on it for a while right before I got pregnant with #2, and after weaning off of it is when my hair went wonky. I blamed it on my pregnancy, and never even thought about a possible connection to the HC.
I started taking it again a few months ago, and my hair actually seems to be recovering, even though I am pregnant again. Hmmm... It could be totally unrelated though.
BTW, I take a combo of "synthroid" and Armour. For some reason too much Armour gave me the jitters, but I feel much better taking some Armour vs just the synthroid. I take the equivalent of 2 grains, and it has my TSH totally supressed and my T3 and T4 levels both in the normal range. I think I am going to try increasing it after the baby comes, and I get my adrenals straighted out again. (Because I am sure I will have to start over with them after the baby is born. *sigh* )