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Thyroid UK
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Understanding lab results TSH 0.025

Hi All

I am confused...not uncommon, but specifically by my most recent lab results.

TSH was 0.025 (range 0.340 - 5.600) and T4 18.6 (range 8.0 - 18.0).

The GP response is 'OK- no action'

It looks to me as if both readings are out of normal range. I take 225 mcg of levothyroxine daily. I've also recently started taking Atenolol ( a beta blocker) for anxiety and hypertension and I am on HRT. It occurred to me that low TSH could be a cause of anxiety levels? I am losing weight but I think sadly that's more to do with dry January than anything else...

Really grateful for any insights!

Best wishes

8 Replies

Low TSH doesn't make you feel anything. And, with a dose of 225 mcg levo, I would expect it to be suppressed. It doesn't matter. Once you are on thyroid hormone replacement, the TSH is irrelevant, unless it goes high. Doesn't matter how low it goes.

On the other hand, your FT4 is slightly over-range - which does surprise me on 225 mcg levo. But, the most important question is : how much of that levo are you converting to T3? And you will only know that if you test it.

If you are a bad converter, you T3 will be low, and that will cause anxiety. Nothing to do with the TSH. So, your best bet would be to somehow get your FT4 and your FT3, tested at the same time, so that you can compare them to see how you are converting. :)

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Thank you, that is a really helpful and informative response. No T3 results on the latest printout the surgery gave me but last year it was 5.4 and the year before 4.4

I'm assuming there should be FT3 results this year as well and will follow up.

Thanks again.

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If your GP has not tested FT3 (many don't now) Blue Horizon do a FT3 only pin-prick test for £29.



Agree. These blue horizon finger prick tests for FT3 levels are great and very accurate.


The only problem with that is, you can't see how well you're converting, unless you do an FT4 at the same time.


If you do a BH test for FT3, it's best to do FT4 at the same time from the same blood draw. That way you can see if there is a conversion problem.

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This is a link from STTM:-


If you go to the date December 20, 2003 on this link:


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Suggest you ask GP to check levels of vitamin d, b12, folate and ferratin. These all need to at good (not just average) levels for thyroid hormones (our own or replacement ones) to work in our cells

Also have you ever had your thyroid antibodies checked? There are two sorts TPO Ab and TG Ab. (Thyroid peroxidase and thyroglobulin) Both need checking, if either, or both are high this means autoimmune thyroid - called Hashimoto's the most common cause in UK of being hypo.

TPO is rarely checked and TG almost never checked. More common to have high TPO or high TPO and high TG, but negative TPO and raised TG is possible, though much rarer.

If you can not get GP to do these tests, then like many of us, you can get them done privately

If your paying for a FT3 & FT4 test, be good idea to check everything. Blue Horizon - Thyroid plus eleven tests all these.


This is an easy to do fingerprick test you do at home, post back and they email results to you couple of days later.

Usual advice on ALL thyroid tests, (home one or on NHS) is to do early in morning, ideally before 9am. No food or drink beforehand (other than water) If you are taking Levo, then don't take it in 24 hours before (take straight after). This way your tests are always consistent, and it will show highest TSH, and as this is mainly all the medics decide dose on, best idea is to keep result as high as possible

If you have Hashimoto's then you may find adopting 100% gluten free diet can really help reduce symptoms, and lower TPO antibodies slowly over time too.

Selenium supplements can help improve conversion of T4 to T3 and may also lower antibodies


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