Thyroid UK
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Isolated thyroid-stimulating hormone (TSH) deficiency?

Has anyone been diagnosed with Isolated TSH deficiency?

I've just seen my Endo for the first time since I had my MRI on the pituitary and some other blood tests taken. Pituitary didn't show anything up and my cortisol was raised, so going to have a 24hr urine test just to see. IGF-1 came back ok along with blood glucose and cholesterol as well.

Endo feels that my symptoms point towards Chronic Fatigue and M.E however although my pituitary MRI came back as fine, he thinks the pituitary is not releasing enough TSH, resulting in my Free T4 staying low/low normal of the range.

I'm on Sertraline and apparently that is being used to help with fatigue, he's suggested I up my Levothyroxine from 50mcg to 75mcg. He thinks in cases like this those two lots of medication used together are a great combination. I asked about T3 however he doesn't think I have a conversion problem just the fact the pituitary isn't releasing enough TSH to raise my free T4.

He never gave a name to this but when I got back I've had a read up and there's a secondary condition called Isolated TSH deficiency, which is supposed to be quite rare, with only 60 patients diagnosed/reported since the 60's and can have it from birth.

I'm 33 now and I've never felt what you would call well and nobody has ever got to the bottom of it. Just hoping that this might be it.

I think what has helped me that has helped him is having print outs of my blood results from a number of years, it shows trends appearing which you wouldn't see from a 1 off blood test. So anyone reading this and struggling for a diagnosis, the more results you have the more they have to go on. My GP had only sent the Endo a few results, luckily I had printouts of a few years worth which I took to show him.

20 Replies

GSP, I've not heard of it and will look it up tomorrow. If your T4 is low doesn't it also follow that your T3 is low? I wonder why he still thinks CFS and ME rather than low T4/T3?


Thanks Clutter.

My naturopath first time I saw him said a lot of patients he sees expressing Chronic Fatigue, M.E type symptoms have a low free T4.

I've read that some people hold the view that before the TSH test came into existence in the 70's that people were treated for hypothyroidism on symptoms but when TSH came in shortly after people who should be treated for hypothyroidism were diagnosed with Chronic Fatigue and M.E?

Is it all a coincidence?


Just for your information. If you go to the date November 20, 2002 on this link and read the answer of the effect of a 50mcg dose of levothyroxine. I note he has now increased to 75mcg but he should take note of your clinical symptoms and try to eradicate them. If he is treating them with something other than sufficient thyroid hormone he is doing you a dis-service.


Is a bit of a long story but after a battle my GP put me on a trial of Levothyroxine at 50mcg this was at the start of the year. Last month was the first time I'd seen the Endo before, he said then I could up the dose. I'd decided to wait till I had the MRI etc and to see him again before upping it which I have done today.

Is early days but he's very good, very knowledgable, nice guy, listens and is very interested in the symptoms. He seems to appreciate that I read up commenting on how well read I was. I said to him yesterday going by what a lot of people say about Endos he's an exception.


The main thing is to have a good Endocrinologist and makes you well.


Isolated thyrotropin deficiency is rarely reported but appears to be not uncommon, often reported under different guises but essentially the same thing low fT3, low fT4 with 'normal' TSH. This can be caused by hyperthyroidism whether due to natural causes or taking too much thyroid hormone. This is why I tend to ask people to hold off increasing medication too much until they are sure they need high doses - e.g. doses that exceed say 150 mcg levothyroxine or suppress the TSH. Once the TSH has been suppressed for some time it tends not to recover or take a very long time.

A problem with a low TSH is that type-2 deiodinase is stimultated by TSH so the patient ends up with some T4 to T3 conversion issues. I suspect this will be minor and 10 mcg liothyroine daily is enough to sort it out.

Low TSH can also be caused by low TRH due to severe non-thyroidal illness and also due to strict dieting, stress or depression. The problem is that if there is depression the doctor tends to put the blame on this and often T3 is required to overcome the depression - a vicious circle.

Your endocrinologist will find that as your L-T4 is increased your fT3 does not increase. Fortunately, a few days ago a paper was published which shows how TSH stimulates the production of T3 . You can request a free copy of this paper under patient access. I suggest you do so and show it to your endocrinologist, although it was carried out in children the results were separately confirmed in a teenage subset. The results are valid for adults.

So your endocrinologist is right in saying your pituitary isn't releasing quite enough TSH and you do not have a conversion problem as such. You are converting T4 to T3 correctly but your low TSH means not enough is being converted. A bit like a car in perfect order but the accelerator isn't depressed quite enough so it goes slow. If you don't get better on 75 mcg L-T4 and your fT3 hasn't increased ask for 10 mcg L-T3 (liothyronine) , a quarter tablet morning and evening. You need to go by symptoms, initially targeting your fT3 and fT4 levels around the middle of their reference intervals (that's where most healthy people are). Do not take your liothyroine on the morning of a blood test, wait until after the blood has been taken.

It may be that you will need higher doses but you will probably do well on up to 100 mcg L-4 plus 10 mcg L-T3 and I'd give this a good try first. It's possible that in time your pituitary will pick up and you may be able to slowly reduce your hormone intake and possibly discontinue it. For this reason I'd try to avoid progressing too quickly to high doses of thyroid hormone as this will make the pituitary issue worse. If eventually you need a lot of hormone so be it, but give the gradual approach a chance first.

I'm studying this area so I'd be grateful if you could pm me in a few months time and let me know how you are progressing.



Thanks for that Jim, sure will keep you updated.

It's worth noting that prior to all of this and being put on a trial of Levothyroxine I saw a naturopath who put me on Nutri Thyroid, Thyro Complex, GTF Complex and Nutri Adrenal Extra. It took about 8 months or so but I regularily had thyroid blood tests and my free T4 raised very slowly. Year last March (2013) my from T4 went from 11 to 15.1 with a suppressed TSH. For some reason in July 2013 my Free T4 plummeted to 9.3 the lowest I've known it.

Anyone have any ideas what would cause this?

I had the ATP test, with the results of that the naturopath put me on a number of energy increasing supplements as as D Ribose, vit B, CQ10 etc. As he thought there should have been more of an improvement in my symptoms

I gave that a try but saw no improvement so was told to stop taking it.

Incidentally I'm still taking the Nutri Thyroid, Thyro Complex etc, was expecting the Endo to tell be to come off of them but he said for me to carry on taking it.


I think your endo is doing OK as it's very early days, I would give him a fair crack of the whip. I would be inclined to wean myself off all the stuff you were previously on as they dind't work, may complicate analysis of your disorder and must be costing a fortune.

With an fT4 of 15.1 you were did not have excessive hormone levels so it is unlikely your thyrotrope (the bit of the pituitary that releases TSH) was upset by taking lots of hormone. It looks like your thyrotrope is under performing (as opposed to the rest of the pituitary) which is good news. It may or may not get better but until it does you will need thyroid hormone supplementation.

It will take about a month before your increase in levothyroxine settles down. I suspect you will need a bit more levothyroxine and a bit of liothyronine as I mentioned earlier but it will take time. Give your endo a fair chance and try and work constructively with him. We get so many awful endocrinologists but some are good and I believe in giving everyone a chance. You will have to go by fT3, fT4 levels and how you feel, the TSH figure will be unreliable in your case.


Thanks Jim, will give it a shot and see how I get on.


I find this replay very useful and answer my question in my today's post.


Hello Jim,

I know this is an old post but I just thought I'd respond because I have ISOLATED TRH DEFICIENCY and you have stated exactly what my endo has stated. Re low TSH and conversion T4 to T3 issues.

I am on a combination of T4 and T3 for that very reason.

I've had this problem for 30 years but was only diagnosed within the last few years as I became progressively unwell.

When I was finally diagnosed my blood results said it all.

TSH 6 ( 0.4- 4.6)

FT4 6.8. (12-22)

FT3 2.6. (3.6-6.8)

In fact I keep a copy of these results in case I encounter any difficulties with other doctors!

I was terribly ill at this stage...bordering on myxoedema coma. A terrifying experience.

I am very fortunate to be under the care of a wonderful endocrynologist who really knows his stuff. He told me right off that I would always need some form of T3 added to my T4.

My brother also has the same problem.

I am currently taking 125 mcgs levo and 15mcgs T3.

I'm not yet levelled off so the final dosages may be different.

Just thought you might find this interesting as you are studying.

Best wishes


Thanks for the reply. Do you have recent blood test results you can post, I'm just interested. Also how are you doing now? It would also be useful if you could pm me with the name of your endocrinologist.



Can the increase in dose from 50mcg to 75mcg cause anxiety, might be a total coincidence but during the past two days since I've started on the increase I've felt really anxious and quite low. Not really felt like this since before I was on Sertraline nearly two years ago.

If it is due to the increase Levothyroxine will it pass and why is it having that effect on me?


I had to battle for many years with a similar problem of a TSH level which just has dwindled away to nothing. Unfortunately the Endo I saw was completely useless and I was left to my own devices to sort out the problems. The main problem with a low TSH is that this is the guiding thing that controls the conversion of T4 to T3/ ReverseT3. The lower the value, the more reverse T3 is generated which blocks the T3 and stops it from operating. When you have a low TSH, its no good taking any T4 as it will all be converted to Reverse T3 which will make you feel really, really Ill. I have been in that situation, and since I have been taking JUST T3 to stop this conversion problem, I am soooo much better!!!! Try reading Paul Robinson's book Recovering with T3, if you want some more info.

Also I have spoken to some of the Medics that deal with head injuries. Were you aware that even a minor bump on the head can damage the pituitary and therefore affect how much TSH it is able to produce even as long as 20 years later? There has been a lot of work published recently from the first Gulf War where even small head injuries have affected soldiers typically 10 to 20 years after their injury and caused their pituitary to stop working and sending the endocrine system to sleep. I know now that I had a head injury when I fainted some 20 years ago, splitting the back of my head open, and we suspect that this is the cause of my TSH /pituitary failure.

Hope this helps



Thanks Heather, that's really interesting, has it effected any other of your hormones? As far as I recall I've really never really hurt my head, the usual hitting your head on something, but nothing serious enough to require medical treatment.


I am afraid that I have lost all faith in Endos because I would have died under their T4 regime, so I have kept well away but I'm not aware of anything else "dropping off" . Instead thanks to T3 I have regained an active life style playing tennis 3 times a week, cycling and walking miles to help the excess weight drop off. I have considerable brain damage caused by hypo-thyroidal dementia which went untreated for many years but enjoy what I can still do within those limits.

The head injury situation is only just being appreciated but its going to be years before the Endos take it on board, perhaps its worth mentioning to your Endo as he seems to be more forward thinking than most. Have you considered just taking just T3 instead of T4? It would take a time for the T4 to work out of the system but if your TSH is very low the T4 is actually making you worse rather than better! The only problem with taking just T3 is that it is short acting and you need to take it in small amounts throughout the day.



Thanks Heather. That's very understandable, sadly I don't have much faith in most health care professionals either. I just feel many a time you're just another stat and not treated like a human being. That's very interesting what you say, the Endo I'm seeing said when this sort of thing does happen, it can be quite often that it is the TSH that is directly effected and that the other hormones can be fine.

My concern is I've had this for a very, very long time, and up until recently it has gone on untreated. I've always thought it was hormonal but have been fobbed off, seen all sorts of specialists etc. been given anti depressants then was told by the head GP at my surgery that my thyroid was fine and that I had nothing to worry about! When I asked him what it could be was told possibly a virus!! If it wasn't for the fact I'd asked for a print out of my results and realised my free t4 was on the low side then I'd have been none the wiser.

Can hypo-thyroidal dementia be picked up on an MRI scan do you know?

Last week I asked my Endo about the possibility of T3, he does prescribe it, but generally only to patients that have primary hypothyroidism and have a trouble converting. He didn't think I had problems with converting and as you mention as the T3 is very active with a short half life getting the right dosage can be tricky. I think that is why he prefers to try the t4 to start with. He suggested I try the increased dose of T4 and see him in 3 months time. Having said that, I'm very pleased with how he listens and takes everything on board, I can't fault him really.

Since I started the increase on Tuesday, I had two days where I felt really anxious, heads felt a little heavy and I had a migraine yesterday, although the migraine is nothing new, as I can get them when my neck and shoulders are tight, due to my job and muscle problems, all connected I've long suspected.

Have you ever had the ATP test? I was seeing a Naturopath and he got me to have the test, is all to do with cellular energy, sadly it's not recognised over here "Yet" by Endocrinologists but my Endo did know about it and showed an interest.

All credit to the naturopath he is very switched on. When the result of my ATP test came back he got me on a number of supplements to try and increase production Di-ribose, Cq10, vit b supplement and a couple of others. Interestingly T3 is a major component of ATP, along with the above so maybe I'm just missing the T3. Unfortunately the energy supplements didn't have any effect on me, but then I wasn't on any thyroid medication only the supplements. It was the naturopath who had said to me that it was worth going on a trial of thyroid medication. T3 was one of the one's he suggests. Unfortunately it was a battle with my GP to get me on T4 let alone anything else.

Through the naturopath I'm on Nutri thyroid, Thyro complex, GTF complex, Adrenal extra and what nobody can explain to me is why over a period of 6 months my free t4 went from 11 slowly up to 15.1 and a suppressed TSH then 3 months later my Free T4 went right down to 9.3nmol. I'd felt better when my free t4 hit 15.1 felt more human. This was before I was put on a trial of thyroxine by my GP. I suppose if my TSH is up the spout, then my results can't be relied upon.

I'd love to know how many people diagnosed with M.E, Chronic Fatigue, Fibromyalgia or symptomatic patients actually have a secondary issue with their thyroid.

I will message you Heather as it would be good to keep in touch, as I don't know of anyone who has this type of thyroid illness. Thanks again!


I have also been diagnosed with isolated TSH deficiency. Is there a way that I can contact you directly?


Hi there!

I just found your post. I know it's a year old but I thought I'd say hello because I have isolated TSH deficiency!

Or possibly isolated TRH deficiency. So I'm either pituitary or hypothalamus.

My endo isn't bothered which it is because they are both treated exactly the same way with thyroxine.

Yes, you're right, it is rare. Very rare.

I am on a combination of T4 and T3. The T3 does seem to raise my mood. Without it my FT3 is pretty low.


Hi, I've had ITSHD for 12 years. I take only T3 as I have a conversion problem. Take care of yourself and acquire as much knowledge as you can. Xx


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