Thyroid UK
84,129 members99,107 posts

The confusing thyroid numbers

Hello! I wonder if anyone has similar problem. After a DeQuervain thyreoditis my thyroid didn't completely recover so I'm on 50 micrograms of Euthyrox. On the last blood tests my TSH was unusually low, in the low normal 0,61 while my fT4 and TT3 were in the lower normal, with TT3 being a bit lower than fT4. I still have symptoms of hypothyreoditis though. I'm feeling cold much more than others , my skin is dry and my hair is not in a good shape. Also, I often feel tired even upon waking up. I'm wondering what the numbers mean since it seems I need to up my dosage of Euthyrox a bit but the TSH number said I should decrease my dosage. I appreciate any reply.



5 Replies

Forget the TSH. At this stage of your journey, it doesn't tell you much. It's gone low just because you are taking Euthyrox - which contains T3 - any form of T3 will lower your TSH. It doesn't even mean your dose is high enough, it certainly doesn't mean you're taking too much.

Just forget the TSH - and the FT4, come to that - and concentrate on the FT3. And most people need that up near the top of the range to feel well. :)

1 like

Thank you so much for the reply! I didn't think about that. Euthyrox however contains only T4 but I guess that doesn't matter. I asked for fT3 but they only could measure TT3 in the lab. I might get fT3 and reverse T3 checked though I'm not sure what that would tell me.

Thanks again!


Oh yes! Sorry, I was muddling it up with Euthyral!

FT3 would tell you how much free/available T3 you have in the blood, as opposed to the TT3 which is free + bound + rT3. You would have a better idea of how well you're converting. Most people need their FT3 to be up near the top of the range.

rT3 would tell you how much T4 is being converted to the unusable reverse T3 (the wrong atom of iodine is removed during conversion) you have. rT3, if you have too much of it, can block the T3 receptors so that normal T3 cannot be taken up into the cells, where it's needed. Given that your TT3 is low in range, it's doubtful you have much rT3, so an FT3 test would be more useful. That's my opinion, anyway. :)


Wow you are really knowledgable, thanks. I am also taking birth control pills for endometriosis for 13 years now. I suspected it might have caused my thyroid inflammation. Yes, I will get the fT3 done. Thanks!


Well, the endometriosis could be due to low thyroid. But I Don't know anything about birth contol pills. Sorry.


You may also like...