Thyroid UK

Bloods/NDT confusion-rama :O

Hi there

after 4 months of NDT, my TSH reading (which the GP is largely focused on) went from 6 to .002. I had stopped my grains the day before.

he said to come off it altogether - and I did (crashed) for a week before getting another round of bloods - TSH still 0.002.

I thought NDT was out of your system in 24hrs? any help/explanations appreciated.

Ive booked in to see alyssa burns in august...


20 Replies

Your TSH is absolutely going to be suppressed if you take any form of T3 in a decent dose. But, it doesn't matter. Doctors believe the myth that a suppressed TSH will lead to osteoporosis and a heart attack. But, it is just that, a myth.

As to taking you off all your NDT, he's either a sadist or a moron! It will take ages for the TSH to come up again, if it ever does. It isn't instant up and down like the mercury in a thermometer. It has to go through several processes and moves very slowly. But it doesn't matter if it doesn't come back up. It's low because you don't need it. I think you should go back on your NDT immediately. Or you're going to make yourself very ill. :(


thanks greygoose

'its low because you dont need it'

do you mean TSH low so NDT is working = don't need to worry about it too much...

and I can concentrate on my high cortisol adrenal fatigue. i am guilty of being impatient about low libido and fatigue symptoms - so didnt realise how much NDT had helped otherwise until i came off it!! :P


No, I meant that you don't need TSH because you are taking T3. TSH stimulates the thyroid gland to produce hormone, but also stimulates conversion of T4 to T3. As you are taking T3 ready-made, so to speak, you don't need that stimulation. What I also meant was that TSH has nothing to do with bones and hearts, all it does is what I said above.

As to whether or not your NDT is 'working', only you can know that by how you feel. If you feel better, then it's 'working'.

TSH is a pituitary hormone. And it is secreted when the pituitary senses that thyroid hormones are low. But, when there is T3 available, the pituitary is served first. So, it could be saying there's enough T3 by lowering the TSH. But what it really means is that the pituitary has enough T3. The rest of the body could be deficient, or it could be not getting into the cells, and you would still be hypo. The TSH is a very bad indicator of thyroid status, and rarely corresponds to the way the patient feels. But, that's just another of those little things that doctors know nothing about!


greygoose, heart and bone problems are a known complication of hyperthyroidism, so I don't think it's quite fair to call it a myth; it's more complicated than that.


Certainly heart and bone problems are a complication of hyperthyroidism, but it has nothing to do with the TSH per se. It is the high T3 that causes the heart and bone problems. So, I think it's perfectly fair. We're not talking about high T3 here, we're not talking about hyperthyroidism. As far as the OP and her TSH are concerned, the TSH has nothing to do with anything very much and it is totally wrong for her doctor to try and dose her by the TSH - especially as she's on NDT - and stop her medication because of a suppressed TSH.

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'It is the high T3 that causes the heart and bone problems.' It isn't as simple as that. For instance in older people low tsh in euthyroid individuals is associated w significantly increased risk for atrial fibrillation.

The reason we're not talking about high t3 is because op hasn't posted his t3 results, so we don't know if his t3 is high or not. I agree that a suppressed tsh isn't a good reason on its own to reduce meds and that decision should be made in conjunction w t3 levels.


The OP is 44, so I don't think that applies, either! I am 71, and my TSH has been suppressed for years, yet there's nothing wrong with my heart. Besides, I have yet to see the proof for your claims. But, have a look at this :


greygoose in the second link Jeffrey Dach MD quotes a study - this is his evidence not mine - which concludes 'People on long-term thyroxine with a high or suppressed TSH are at increased risk of cardiovascular disease, dysrhythmias and fractures. People with a low but not suppressed TSH did not have an increased risk of these outcomes in this study. It may be safe for patients treated with thyroxine to have a low but not suppressed serum TSH concentration.' Here is the link: He uses this study alone to justify his claims that it's a 'medical myth' that there are health risks when tsh is suppressed.

In that same article he also says 'Thyroid excess is easily avoided by simply stopping the thyroid medication' which is what hemmingwayjr's doctor did that made you call him 'a sadist or a moron'.

The relationship between tsh, t3 and t4 is complex, and ideally we'd have doctors who were up to the task of appreciating that complexity.

I appreciate that you may have arrived at your opinions about doctors because you've been let down by them, as have I. But I'm not willing to go it alone just yet, so I'm trying to make myself an educated self-advocate, like a lot of people here. :-)


As far as I'm aware, no-one has asked you to go it alone. So, I don't see what that's got to do with anything.

It seems to me, you are just arguing for the sake of arguing, nit-picking, and taking things out of context, ignoring what doesn't suit your argument, without providing any proof of your own. Well, I've decided I'm not going to indulge you anymore. This is my last ever comment to you. :)



I'm sorry you're upset.

My tsh is also suppressed. When my t3 is high in the range (in order to keep me feeling well) that's what happens. I take what I consider to be a well-documented risk that it may affect my heart and/or bones because I can't live my life w lower t3 or on levo alone. I present this point of view not because I want to argue with you but because I think it's important to know that there is scientific evidence (even if you feel it is contentious) that there is a risk involved. A lot of people are prepared to take the risk if it means restoring health and well-being.

I'm sure you understand that we don't always agree on this forum. That's okay. I've learned a lot here from people whose opinions are different from mine. I'm happy to disagree peacefully.

I wish you all the best. :-)


hemmingwayjr it can take weeks for meds to leave your system, and taking t3 (in your ndt) can suppress your tsh for some time, even after reducing or stopping medication. Having said that, your t3 level is important in determining whether or not you're overmedicated. Did they test your t3?


Hi puncturedbicycle

free T4 was 17.4 pmo/L (range12.00 -22.00) and free T3 6.3 pmol/L (range3.10-6.80 pmol/L)

they were unable (lost??) to give me the test results from ten days earlier when I was still on NDT, but the doctor had said at the time of the second test results that t3 and t4 had both come down to normal range...

I am currently on 1 grain of NDT a day and am going to build more slowly to 2 or 3 as instructed elsewhere on this site. I went to 4 grains over 3+ months so prob moved too quickly?

cheers & thanks again


Many thanks hemmingwayjr. That is quite close to the top of the range. It sounds like you need to build your dose more slowly and test every so often. Too much testing too soon won't help. You need to be on a stable dose (try 1.5-2 gr) for long enough (try six weeks) to know where you are.

Hands up, I don't know much about ndt, but if you look at a conversion chart it says that 3 grains is roughly equal to 300mcg levo, which is quite a high dose. You may need it - some people here are on high doses - but just know that's the exception not the rule.

It sounds like your doctor panicked because all your bloods - not just tsh - showed overmedication. Of course it would have been better if you'd just been allowed to reduce your dose and retest. Unfortch second blood tests aren't helpful if you had stopped meds. Test results will show falling levels but nothing else.

I know there are advocates of the 'increase until you feel well' school of thought but changes in my symptoms were so subtle and some things took so long to resolve that that was impossible for me. I felt great when I was overmedicated, then got hyper symptoms, then on the same dose I got hypo symptoms.

I tried ndt and became extremely hypo when I couldn't tell if I was on enough meds or not, so for me this way of working isn't practical. For whatever reason my pulse rate doesn't change a lot on too little or too much medication so I get little physical indication of where I am.

Lack of libido may take a while to resolve, or it may be caused by something else (in which case thyroid meds won't help) or, sadly, it may not come back at all. But in raising your meds indefinitely 'until you feel well' you may find it's too fine a process to know what's going on and you'll go over or under the dose that's right for you. Or that is what I found anyway. Hope that makes sense.

Just another thought (I may have asked you this on another thread) - have you had sex hormones tested? That's another route to try.

Good luck to you. I hope you feel better. :-)


Ignore the stupid GP and go by how you feel not numbers.


thanks for your comments. puncturedbicyle not sure you got my reply, but i will pick up test results tomorrow... peace & a good recovery to all!


How funny, the notification only showed up this afternoon but your reply says it was posted yesterday. (I replied above.)


Thanks again PB.

I think with hindsight I was impatient for relief from symptoms (for my GF too) so will go easier with the NDT dose this time... then get tested again in a month or two... There were no hyper symptoms temp and pulse wise... and i certainly crashed when i came off them.

ps my testosterone last week was just over the upper range of 29.00 at 30.4

pps My two Gps so far do seem to be living up to the opinions of many on this sight. the first told me to try exercising more even though I was in the best shape of my life and swimming every day... the second suggested anti depressants 5 mins in even though my TSH readings were high both time 9, then 5.9. hopefully doc alyssa burns will eb able to help too.

have a great weekend.


Yes, v predictable. I think they have stopped listening, so they go straight to exercise/antidepressants even if you're already exercising and aren't depressed. :-)

Not all docs are like this. I met a new gp in my surgery who told me right off the bat that the reason I felt awful was because my levels were always fluctuating, and although she only knew of t3 as a medication used for thyroid cancer she agreed to continue to prescribe it. And that was just a random appt, so I got lucky.

Now of course there's a very long wait to get an appt w her! And I'm just waiting for a higher-up to put the hard word on her about my t3 script.


I'm not contemptuous of Doctors... just a little shocked about how out of sync their solutions were with the problem - and aware they prob see 40 people a day. Good luck with your t3, and thanks again to you and greygoose for your thoughts. :P

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Sorry to resurrect an old post. Just seen that no one had answered one of your questions about how long it takes NDT to leave the body. NDT contains both T3 and T4. The half life of T3 is about 6 hours, and T4 about 6 days. This means the T3 will be largely gone within a few days, but the T4 will take weeks. 4 or 5 weeks is what they say to clear it to prepare for RAI treatment. For me, I get a big crash at about day 3, which I assume is when all my T3 is used up. Other people feel the first crash within one day, and is why some people take a split dose.


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