T4-T3 combo and test results: Can someone help... - Thyroid UK

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T4-T3 combo and test results

Can someone help with these please?

Just had these blood tests back, do they look OK or should I increase my T4 a bit?

Been feeling a bit 'borderline hypo' again for the last few weeks which is why I sent off for these blood tests.

TSH Low <0.005 (0.27 - 4.20)

T4 Total Low 59.2 (64.5-142.0)

Free T4 Low 9.83 (12-22)

Free T3 6.03 (3.1 - 6.8)

I'm currently taking 50mcg T4 and 37mcg T3

6 Replies


FT4 is low because you are taking proportionally more T3 than T4. It doesn't matter that FT4 is low because FT3 is good in the upper range.

You appear to be optimally dosed so perhaps you could check your ferritin, vitamin D, B12 and folate.


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.

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Thank you Clutter. I have these results for

Ferritin = 179

B12 = 666

folate = 8.8

These are all flagged as within normal range but not had Vit D tested, maybe I should do that



They look fine. Ask for vitD to be tested. It's often deficient in hypothyroid patients.


Thanks, will do x


TSH means nothing when you are on any form of thyroxine.


A T3:T4 dose ratio of 1:1.35 is really low. Customarily, T3:T4 will be between 1:4 and 1:10. Seems to me you should increase FT4 to get it up into the normal range.

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