Thyroid UK
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Does taking T3 with T4 suppress TSH, evidence please?

I am taking 115 mg T4 and 10mg T3 daily and I feel reasonably okay. But my annual check has come round and now I need the 'TSH is suppressed' conversation. GP wants me to reduce my dose due to suppressed TSH. Its been suppressed for some years and so far I have avoided reducing the dose, but as I am 58 and 'menopausal' GP are getting agitated. Recently I decided to reduce my T4 from 125 daily as I was getting some occasional mild palpitations, which have now stopped, and I don't want to reduce further as when I reduced it to 100 mg t4 I felt bad.

Please has anyone any articles which dispute the link between suppressed TSH and osteoporosis and/or indicate that taking some T3 can suppress TSH.

I feel okay and am also doing weight bearing exercise.



3 Replies

I don't know if the following is helpful but you can email and ask for a copy of the following article in Pulse Online by Dr Toft, ex President of the British thyroid association, of which this is an excerpt:-

6 What is the correct dose of thyroxine and is there any rationale for adding in tri-iodothyronine?

The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range – 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l. Most patients will feel well in that circumstance.

But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This ‘exogenous subclinical hyperthyroidism’ is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l).

Even while taking the slightly higher dose of levothyroxine a handful of patients continue to complain that a sense of wellbeing has not been restored. A trial of levothyroxine and tri-iodothyronine is not unreasonable. The dose of levothyroxine should be reduced by 50µg daily and tri iodothyronine in a dose of 10µg (half a tablet) daily added.


This is a link re osteoporosis and their are lots of interesting topics at the top of the page.

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Dear Shaws

thanks very much, I will have a look at this, also saw the other post about TSH, oh dear its all very complicated



It is only complicated because really we shouldn't be having to research to get ourselves better but if we don't it is us and our families who suffer in the end.

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