It could also be mitochondrial calcium.
I just ordered extended release caffeine tablets. I want to see if that works better than drinking coffee because I do get improved brain function from my lattes but tend to get a mild crash afterwards.
My mother in law had her thyroid removed several decades ago and she only takes levothyroxine without any T3. She's been drinking coffee pretty much non-stop throughout the day ever since, literally non-stop - and she manages to function pretty well that way. I suspect she's able to keep her T3 at decent level because of that.
That's very interesting. I have normal spina-gt, but low spina-gd, and taking coffee helps immensely. I don't usually experience crashes afterwards.