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Thyroid UK
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What happens to TSH levels when on T3 treatment? What are optimal levels?

I'm sure I've read before that when on T3 the TSH levels should be ignored? Is that correct? My daughter has been on T3 for approx. a year following RAI and was picking up pretty well. Unfortunately her endo moved (no idea where to else we would follow him!) and she is now being treated elsewhere. They reduced her T3 and added T4 and she is much worse than before. A recent blood test shows her T3 level as elevated (much higher than it was). I'm going with her for next apt next week to challenge their treatment, but I don't take T3 myself and am hazy about what I should be looking for/ignorning. can anyone point me to info about this? I did buy Paul's book but my dear brother has lost it and although I will probably give in and buy another, it's unlikely to be here before her apt early next week. any pointers gratefully received

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This is an extract and other questions on the page may interest you. Most Endos know little about prescribing T3 due to the guidelines laid down by the British Thyroid Association:-

For someone taking 100 mcg of T3, we expect your pattern of lab results—a low TSH and high T3. However, your TSH and T3 levels are irrelevant to whether you're overstimulated or not. Two studies we just completed confirm other researchers findings: these tests are not reliable gauges of a patient's metabolic status. Many patients taking T3 have TSH and T3 levels like yours but still have severely low metabolic rates. Their metabolic rates become normal only when they increase their dosages further. Their metabolic rates become normal and they have no detectable overstimulation.



Thanks Shaws, this is really useful. Can you tell me how to search Dr Lowe's site? Obviously the links don't work.


I have tried the above link and it will take you into the archived site.


Hi shaws, the link you provided did work, but was so interesting I tried to navigate to some of the other links on the page, which didn't work. I was wondering how to navigate to other links on the archived site


Unfortunately, that is the problem.Dr Lowe died last year without a Will and there was an issue with Probate. The topics at the top of the page are accessible but not links within. Usually, the link he referred to is somewhere. It is just luck. His Book - The Metabolic Treatment of Fibromyalgia is, I believe, out of print. I have just looked on Amazon and there are two listed - around £1,000 each. It is a Research and Reference Book.



...Paul does have a website with an informative blog rwt3.com hopefully you will find the information you are seeking.....


If the t4 is not being converted into t3, then it needs to be broken down so it can be got rid of. It breaks down into reverse t3. (An inert substance). T2 and t1 . Unfortunately, reverse t3 will show on a test for t3.

To me, it rather looks as though the increase in t4 has resulted in a raised rt3, which will be stopping your daughter from using up any free t3 she may have had. She needs a reverse t3 test, alongside a free t3 test..... So she can see if rt3 is a problem. The more she raises the t4. The worse her symptoms will be if she is suck in an rt3 merry go round.

Insist her doc treats her symptoms not her test results.



Hi Galathea, this is exactly the information that I want to take with me - a demonstrable understanding of what could be happening to her, and why the tests are required. Thank you so much!

It never fails to amaze me how knowledgeable and willing to help everyone on this site is - without it I would still be very ill but having learnt I am now much better - I intend the same for my daughter!

Thanks again xx


In that case, its probably best if you take in one article which explains what the problem is with rt3 levels being too high and how it stops use of free t3 by the body.

Dr Barry Peatfield wrote an article about this, which was easy to understand and it used to be available on the tpauk website. However, the tpauk website no longer has the same info available so you may have more of an Internet search on your hands.

I am not sure if the Nhs measure rt3, it may be an alien concept to them. There are several rt3 groups around,there is certainly a yahoo group.

Good luck.. And happy googling,

G xx


I think the NHS are still in the dark ages regarding rT3 testing. I think it can only be done privately - still!

My personal experience showed that my problem was at least partly rT3. After about 3 months on T3-only it suddenly cleared and I went hyper. I now only need 75mcg instead of the 125mcg I was needing! I think you may have hit the nail on the head with this one and rT3 may well be the problem.

Carolyn x


I asked my Endo to do this, and they say they don't, wonder why? Could it be that they are too frightened that we are well versed in this topic now and have no knowledge of it really......? Me thinks so.


Re Galathea's response. This is Dr Peatfields's article:-


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Thanks once more for this info and the article - I think it's one I have to re-read a couple of times before I understand the full gist, but all of this is so helpful x


My endo doesn't believe in rT3 causing problems. I think I was suffering with this exact problem when on T4 only. I had a suppressed TSh, slightly over range fT4 and top 25% fT3. I felt absolutely dreadful :( I am now on NDT (which contains T3), have a suppressed TSH, mid range fT4 and interestingly, same level of fT3 a I had on T4 only, and I feel pretty well. So apart from a much lower fT4, my results look very similar, bu I couldn't feel more different :). X


Thanks Clarebear. I'd like my daughter to try NDT but she wants to try the NHS options before going down any self-prescribed route. I'm hoping that armed with enough information at her apt, that I will be able to argue for a trial of NDT via her endo if he can't offer an alternative which will eliminate her symptoms. Watch this space ....


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