I've been on thiroyd for about 3 months. I'm up to 3.5 grains. When I was on 2.5 I had blood tests and my FT3 was in range but low. I'd been on 100 mcg of Levo before, so if the 60mcg equivalent is anywhere near correct I was already taking the equivalent of 150mcg and still under medicated. Has anyone else found this? My iron, folate, ferritin etc are all fine, so I should be absorbing the T3 ok.