@lulueatsmeat T4 is a longer term, slower acting molecule which addresses dysfunction of the thyroid gland itself, mostly, and can make things worse without T3; I suspect because of your history which was similar to mine, this is a simple liver glycogen issue. So, as a (hopefully) one-time thing to knock the system back into balance, T3 makes a lot more sense. I don’t take t3 any more and I’ve never taken t4. I’ve only taken t3 at that ~6.25mcg dose 2-3 times in total (around 2016) to help with sleep. It made me feel amazing immediately, completely shut down stress and made me warm and peaceful. And then my sleep was back on track forever after that. But you must must must take it with a good amount of some kind of carbohydrate otherwise you definitely will have a stress reaction. Mexican Coke worked well when I took it. I imagine fructose-heavy carbs work best so the liver can have first crack at absorbing the carbohydrate and storing it for the overnight sleep.
Peat said magnesium glycinate is the only oral form he knew about which didn’t give people bad reactions or digestive upset. Epsom salt bathing definitely makes a positive difference for me and I do it often. Never tried transdermal magnesium spray but I don’t see why it wouldn’t work. Best of luck!