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Thyroid UK
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TSH and T3 levels

Hi, 1st time on here and just wanting some advise. i have an under active thyroid and was put on thyroxine several years ago. i have been on the same dose ever since although i have lost 10 stone in between! i am constantly drained and feel weak. my results have just come back as TSH level 0.78 miu/l and T3 at 1.4 nmol/l the doctor just says its normal but the TSH seems quite low.

Any Ideas

5 Replies


For members to be able to interpret your results, you need to add the reference ranges as they vary from lab to lab.

We really need TSH, FT4 and FT3.

Also very useful would be

Vit D




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Hello scottharding, well done for losing 10 stone! Apparently slim people need more levothyroxine than larger people. Could you put the lab ranges for your blood tests along with the blood test results? labs vary and it's hard to make sense of the results without the ranges. You can edit your post to include them. It's the FT3 result you need to be clear about.

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It could be that you are on a dose that is a little bit too high as both under and over active can cause tiredness. Your doctor really needs to measure your fT4 as well as TSH since levothyroxine will raise the fT4 figure. Your 'T3' figure appears to be for 'total T3' rather than 'free T3' going by the 1.4 nmol/l figure. Total T3 is useless, you would need the free T3 (fT3) figure if measuring T3.


For full evaluation you ideally need TSH, FT4, FT3, TT4, TPO and TG antibodies, plus vitamin D, folate, ferritin and B12 tested

You are unlikely to get full thyroid and vitamin testing from GP


Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers.

All thyroid tests should be done as early as possible in morning and fasting and don't take Levo in the 24 hours prior to test, delay and take straight after. This gives highest TSH and most consistent results

Essential to know if you have high antibodies- this is Hashimoto's also called autoimmune thyroid disease

Link about antibodies



a TSH of 0.78 is not low, it's quite good. It's more likely that you are low on Ferritin, Vitamin B12, D, Folate, or all of them. For some reason it seems that people who have thyroid issues don't absorb these nutrients from their food properly even if they have a healthy diet. Many of us supplement to bring our levels up to at least half way in the normal range.


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