Thyroid UK
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I have been hypothyroid for 15 years and on medication but the symptoms recently got worse. I saw the thyroid specialist today who refused to give me T3 supplement despite my symptoms, because my blood tests showed T3 in optimal range TSH within normal range and T4 below normal range. T4 therapy made me feel worse, Armour helped for a while but I feel I'm not converting, I think I don't have enough T3 at cellular level, having done lots of research on various thyroid sites. Does it make a difference how soon after taking Armour thyroid you have the blood test? Will it show different levels in your blood if you took your medication the day before but waited until after the blood test to take that day's medication?

I believe my T3 levels could have shown optimal because I had just taken my tablet before the blood test?

I have decided to order my own T3 but my doctor whilst advising me against this has agreed to monitor my progress. I understand why he has refused because if he had prescribed something while my blood shows normal and something awful happened then he would probably lose his job, so I am grateful for his involvement at all. But I like many other think the tests are flawed, what can we do about this???

4 Replies

Acunatang, taking Armour before your blood test can affect the results as it will measure the peak rate of thyroid medication in your blood rather than the normal circulating level. It's unlikely to have made an enormous difference to FT3 5.7 though. You can order a private FT3 test fromBle Horizon or Genova if you want to be sure.

I'm not aware of any tests which measure T3 at a cellular level.

FT4 is often low when taking NDT because the T3 in it makes higher levels of T4 unnecessary for conversion to T3. You are taking direct T3 which doesn't need converting. Your FT3 serum level is good, be very careful that taking more T3 doesn't make your FT3 over range.

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Yes I know my T3 level looks good (which does concern me regarding T3 supplementation) but there is no other explanation for my worsening of symptoms, I have always felt that my body is not converting and I have read research which indicated that very often your blood tests can show normal even when your T3 is not optimal at a cellular level.


You might want to consider getting a Reverse T3 test. I know Genova Diagnostics does one, and I think Blue Horizon might do as well.

There is a lot of argument over the importance (or lack of it) of reverse T3 and whether dosing with T3 only is needed to reduce it. I'm not qualified to say anything about anything.

Some of the differing opinions :


I have already ordered my T3, I was told by my endo that they can't test for rT3 so have based my diagnosis on the following information found on the NAH site :-

I have high CRP

There is a direct inverse correlation between CRP and reduced tissue T3 (112,270), so individuals with elevated CRP (greater than 3 mg/l) or other inflammatory cytokines will have a significant reduction in cellular T3 levels. The suppression of intracellular T3 levels correlates with the degree of elevation of CRP, despite serum thyroid tests being “normal” (112,270). Thus, if any inflammation is present, which is found in numerous clinical and subclinical conditions (as above), the body will have lower cellular T3 levels that are often inadequate for optimal functioning; but the pituitary will have increased levels of T3, resulting in a lowering of the TSH that would potentially be inappropriately interpreted as an indication of “normal” thyroid levels.


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