Posting this because I sometimes see questions here about hair loss. For me it has been a hypo symptom but it didn't go away even when on the 'right' dose of levo.
I still don't understand why when my bloods looked good on levo (tsh under 1, t4/t3 high in range) my hair continued to thin until t3 was added separately. (Other symptoms relieved by the addition of t3 are constipation and oedema, which did not respond to levo alone.)
I have never seen this discussed or explained until I saw this in the comments here: restartmed.com/reverse-t3/
I still seem to have a fair bit of hair fall, but it always seems to be growing well, which seems to reflect what Dr Childs is saying.