Just to throw this one in, I haven't seen any difference with the effects of alcohol before and on T3, but had noticed my tolerance seemed to be dropping as my health (lots of hormones out of whack) deteriorated.

I have since worked out that this was actually down to just one of those out-of-whack hormones: insulin. What was happening wasn't a case of one drink and under the table, it was one drink, a huge insulin spike and then hypoglycaemia.

Having experimented a little, with the aid of my trusty glucometer, I've found that if I'm going to have a drink, I need to get some protein (and fat) into me FIRST. Then no problems. So, the old rule about not drinking on an empty stomach is even more relevant for me.

So, a possible answer to the question may be an effect of thyroid hormones on insulin response, or something like that.