Thyroid UK
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On T3 only and having a 'dip', any other tests I should request from GP

Hello. Have been on T3 only for over a year after having two thirds of thyroid removed 5 years ago and no success on T4 or NDT.

The T3 has been great - really got my life back, but have been sliding over the last few weeks and feeling rotten at the moment. Exhausted, dizzy, aching back, legs giving way, ears ringing, sharp pains around my body - the list goes on :-)

So am off to GP tomorrow and thinking I should see if they'll do the following tests:

Free T3 (am I right in thinking this would be the only relevant thyroid test as I'm on T3 only?)




Vitamin D

Should I be asking for anything else?


8 Replies

You may need an increase in your T3 but you must be disappointed to have symptoms re-appearing.

I think the list of blood tests is good and he should also do T4 and TSH. When you get a print-out of the results with the ranges, post again and someone will comment.


Thanks :-). Yes, feeling quite down about it to be honest. The T3 was given to me by a specialist in the UK and I live overseas where they don't seem to prescribe it, so I have taken charge of my own increases and decreases (extremely cautiously!).

Whatever's wrong with me at the moment doesn't seem as if it's an increase I need, or maybe I need a big increase - I'm just not sure. Maybe I need to reintroduce some T4.

It feels like such a minefield as so many other factors sometimes need to be considered. Problem is when you're not feeling well this can seem like such an insurmountable task :-).

Thanks for the test advice.


I actually would not 'bother' with fT4 and TSH, if you've been on T3 only for that long your TSH will be suppressed and your fT4 non existant! so yeah, only fT3 :)

My bloods are like that: suppressed TSH/non existant fT4, I've been on T3 only for 9 months now, am on 140mcg daily.

also ask for 'iron studies' (that tells you iron/iron binding capacity and iron saturation)

those things are the 'main package' anything extra is a bonus ie: magnesium/potassium/sodium (potassium and sodium are in the renal function test and your GP will probably be happy to do this one)


NBD - Would RT3 be worth having do you think?




No Louise, rT3 is also a waste of time/money/resource if someone is on T3 only as rT3 is produced by T4, not taking any T4 and the thyroid being suppressed you already know that in a person taking T3 only there will be negligible rT3 :)


Ohhh! Thanks! :-) Wasn't sure exactly how it worked! :-)




besides: the NHS does not test rT3 :(

but if someone is not medicated or on Levo or on NDT (or a combination of these) they can have it privately.


Thanks all of you. GP was helpful and am going back on Monday for blood tests. They are testing free T3, cholesterol, B12 and doing 'iron studies' too. They don't do Vit D testing. I will post results at the end of next week when I get them back.

Thanks again.


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