Thyroid UK
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T4 not dropping. why?

I have had extreme hyperthyroid symptoms and my T4 has been stuck at 24 (don't have ranges) with TSH 3.26 and FT3 at 3.0 for the past 9 weeks. I have Graves and had RAI 9 years ago and no trouble until 4 months ago.My synthroid was lowered 3 times and stopped entirely 2 weeks ago. Anyone have any ideas on what's going on and when I should see improvement? I am going crazy with all the symptoms, 9 weeks off work and no answers. I see my endo in 2 days. Could it be a conversion problem?

3 Replies

Has your thyroid regenerated itself? This is a known and documented phenomenon. However it is odd that you have relatively high TSH along with over-range FT4.

In my book you should have an ultrasound scan and, ideally, an MRI to look at your pituitary. Plus tests of some other pituitary hormones such as prolactin.

I am a bit confused by the combination of USA branded levothyroxine "Synthroid" and UK-type FT4 values. Where are you?



I am in Canada. I have since had an ultrasound and it appears my thyroid has regenerated and has a small nodule. My Synthroid has been reduced drastically and T4 has dropped. Waiting to retest and adjust further. Sorry for slow response, but I have other family crises ongoing and am also dealing with depression now, SSRI side effects and a cold!


Take your time! It really doesn't matter. :-)

It is really good that there is now a finger pointing at a possible explanation. That is the first step in achieving resolution, which I sincerely hope you do.


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