Thyroid UK
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How much t3

Hi it's been a while since I posted anything here , I was just wondering how much t3 I should be taking . I've just increased my thyroxine from 125 to 150 , I am currently taking 10 mg t3 , do I need to increase my t3 also ? Or just carry on taking 10 mg , doc hasn't a clue about what t3 is for or why I am on it . It was dr Toft who prescribed it for me many years ago . I still have terrible foggy brain and depression , anxiety . I have increased my thyroxine myself . Doctor told me to leave it as it is , because my blood test results are normal ( dosn't matter how I am feeling ) 😁

I will be very grateful for any advice about this

Thanks Sandra.

5 Replies

It would be helpful if you could post your lab results - with the ranges - otherwise people will have no idea how much T3 you should be taking. :)

But you shouldn't increase both at the same time. One or the other, and then leave it a while, test, and see how you're doing.

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My latest results 17 ( 9-21)

Unfortunately I don't have my t3 results . They never do that one anymore . My tsh is always suppressed 0.01 don't have the range sorry .

Thanks for your reply grey goose


Doesn't matter about ranges for the TSH - a TSH is always a TSH - if you see what I mean.

OK, so your FT4 is good. But no-one can advise you on T3 without seeing the FT3 and knowing how well you are converting.

Would it not be possible for you to get it done privately? The FT4 and the FT3 at the same time to get an idea of your conversion. There's no fixed amount of T3 that anybody should be taking, it depends on the individual. If you are converting well, your FT3 will be higher in range than the FT4, so you won't need more T3. But, if you're not converting well, it will be lower. We need to know that. Sorry.


You can get the t3 done privately with blue horizon medical. I had my tsh, t4 and t3 done two weeks ago with their finger prick test, cost £49 I think. Results back within 48 hours.


I am not medically qualified but believe your dose of T3 may be too small to be of benefit.

If you go to page 80 on the following link and on the top of l/h column you will see what was found to be the best equivalent combination of T4/T3.

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