T Nation

Normal/Good TSH but elevated Free T3--What's going on?


So I just had some thyroid tests done since it has been a long time.

TSH: 0.98 (0.3-4.7 mcIU/mL)
Free T4: 1.5 (0.8-1.6 ng/dL)
Free T3: 418 (222-383 pg/dL)

Previously, a few months ago in October, my TSH was 1.98, Free T4 was 1.3, Free T3 was 282. I have not been assessed for any autoimmune thyroid problems+did not knowingly palpitate thyroid recently (unless somehow you can do that by accident?). Also I do not supplement iodine or selenium.

So what could b going on here--normally TSH should drop with increased Free T3 right?


The key to this is your waking and mid-afternoon body temperatures. These might suggest that rT3 is blocking fT3. Otherwise with high rT3, you should be warm and having some hypo symptoms.

I don’t know, but speculate that rT3 might blind the hypothalamus to the fT3. Never seen anything addressing that, so its guess work for me.

fT4 is also above mid-range.

If there was a thyroid hormone producing nodule pushing up fT3, fT4, TSH should go down as you expect. I have never considered the implications of a small degree of hypo coupled with rT3 - another “speculative” idea.

Whats going on with fat gain/loss?
Feel edgy or agitated?