I posted a question about my labs on July 19th...and since then, I decided to do some research. I am concerned that my TSH is low as well as my FT4 is always low...and wonder if that means that I could have rare pituitary secondary hypothyroidism? Research seems to show that when TSH and FT4 are both low, that's what it could be. After the birth of my son 16 years ago, I was diagnosed with Graves and immediately sent for RAI, though I now think it was a wrong diagnoses. I have been on Armour for most of that time and my labs are always low...when I look at them over the years. My FT4 is almost always on the very low end of normal and sometimes even out of low normal range slightly. My last labs were TSH 0.03 on range of 0.5-5, Ft3 3.3 on range of 2.0-4.4 and Ft4 0.62 on range of 0.58-1.64. I am currently on 120mgs of Armour. I tried a combination of 90mgs of Armour with 25mcg of Synthyroid a few months back and it made me worse hypo with a FT4 of 0.47. I have heard that the TSH can become suppressed after being on Armour for so long, which is what I think may be happening; however, sometimes I wake up in the middle of the night and I feel like I can feel my heart racing enough that it wakes me up. It will slow back down quickly, but I am concerned about this. I do recall that even when I once had a TSH of 32 my heart would race and I would have hyper symptoms such as diarrhea, high blood pressure, anxiety even though I was obviously hypo. so, if I tell my doctor about racing heart at night, he will likely reduce my Armour meds...which might make me more hypo. I'm not sure. My big concern is why does it seem that my FT4 never goes up very much? What can I do to improve that...and does it mean that I could have a pitiutary issue? Should I be concerned that my TSH is so low? Am I just worrying too much? Thanks for some guidance here.