Hashimoto's, Normal Labs, Still Exhausted on Levothyroxine
If you have Hashimoto's, take levothyroxine, and your labs are "perfect" but you still feel awful, there is a mechanism for that. Levothyroxine is pure T4, and T4 has to be converted to active T3 to do anything. When that conversion fails, more T4 does not fix it.