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Thyroid UK
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Help interpreting results please? High RT3, hypothyroid symptoms

Hi All,

Can anyone help interpret these results? I have a lot of hypothyroid symptoms including low basal body temperature of about 35.8C. I think maybe it's a problem

of conversion? Anyone know how to help that? I feel dreadful & need to get better. Dr Myhill not taking new patients & I'm just at a loss. Although my TSH was fine this time, a previous blood test 3 weeks before that it was 4.9 (but that was NHS so in their reference ranges). I also has a TSH come out at 8 a few years ago. What is going on here? 

Urine thyroid hormones

T3 - 809 pmol/24hr (800 - 2500)

T4 - 1,070 pmol/24hr (550 - 3160)

T3:T4 ratio - 0.76 (0.50 - 2.00)

Blood thyroid hormones

Total T4 - 134 nmol/L (59 -154)

TSH - 1.69 mIU/L (0.27 - 4.2)

Free thyroxine - 16.8 pmol/L (12.0 - 22.0)

Free T3 - 4.9 pmol/L (3.1 - 6.8)

Reverse T3 - 28 ng/dL (10 - 24) 

Homocysteine - 12.50 (desirable level up to 10 Umol/L)


5 Replies

Welcome to the forum, Martha2015.

Are you taking thyroid replacement?

Homocysteine can be raised when B vitamins are deficient.  Have you had B12 and folate levels checked?  Supplementing B vitamins may reduce homocysteine levels.



I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


Hi! Thanks! No, I'm not taking thyroid replacement. Martha



High rT3 is often caused by unconverted thyroxine.  Obviously not in your case.  I'm not sure that there is anything to be done when rT3 is naturally high.


Optimising vitamins and minerals is a good plan to start with. It's good for people anyway but it should also help improve conversion from T4 to T3. And the hope is that the proportion of T4 converted to rT3 will reduce and the amount converted to T3 will increase. It is inadequate levels of Free T3 that make people feel hypothyroid.

I would check levels of vitamin B12, vitamin D, folate, ferritin, and a full iron panel if possible. If there are still problems then check out zinc, copper, selenium, magnesium, vitamin A. Money is usually the deciding factor in what gets tested - it is for me anyway. I've never had the second group of things I mention tested.

The other thing to look into is adrenal function. Having cortisol a bit too high or a bit too low can have big effects on overall health and thyroid function.

Free T4 is not that great (but isn't outrageously bad either) - it is in the lower half of the reference range (just). Improving the things I've suggested may help.

If you get the vits and mins tested that I suggest, get the results and the reference ranges and post them on here in a new post, and ask for feedback and recommendations for supplements.

Info on testing can be found here :


Ask if you have any questions about all this.


Thanks so much! I definitely have iron problems & vitamin D. Is there ever a case for T3 replacement therapy? 


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