Of everyone that I've helped use thyroid hormone, I have seen 2 people that have had issues. One of them was predisposed for sure, as his mother had quite a history of thyroid problems. The other guy may or may not have had a genetic predisposition. Both did bounce back but it took more work than it does for most people. If you have a family history of thyroid problems, I would consider you to be at more of a risk for problems, but most everyone I've helped has bounced back quickly, feeling better once off, after a couple of days, and restored to normal within a couple of wks. 

I never suggest that anyone goes past about 75mcg and I would tapper up to that, over a long period. Usually, they way I'd suggest using t3, is to start with 25mcg and add 12.5mcg every 2 wks, going no higher than 75mcg and using it for no longer than 10-12 wks total. From there, I would tappe back down,, by 12.5mcg every 3 days. when you get back down to 25mcg, stay there for a few days, then go to 12.5mcg.

BTW, Anything above 25mcg, I split into two daily doses