Thyroid UK
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TSH 40 Advice please

Hello. I'm wondering if anyone can help me please. I have been on thyroxine for many years for underactive Thyroid.

My usual dose has been somewhere between 125 and 175 per day for many years.

A recent blood test has shown my TSH to be 40.

I'm not sure what it is meant to be?

My doc just told me to increase my dose from 125 to 200 per day.

Any help or advice would be appreciated



22 Replies

The upper limit for a TSH is around 5 but it is usually considered to be better around 1 and some people seem better when it is lower. When your body is crying out for thyroxine then the TSH rises hence your doctor wants to increase your dose. Increments are usually taken in 25 mcg increments but as you have been on 175 before then has suggested 200. Have you recently lowered your dose?

It would be useful that after each test you asked for a printout of your results and the ranges. The ranges are important as they differe from lab to lab. Is this the only test result you have been given? It would also be good to have the fuller picture with FT4 FT3 and antibodies. T4 is the medication you are taking but is inactive. It converts into the active form T3 which is what you body needs. The reading to go with them is FT3 and FT4 and this is the free bit that is in the blood stream. There is no guarantee though that enough is getting into the cells where it is needed. The Thyroid UK site explains this so have a read and if there is anything you don't understand then please ask.


Thank you. I'm a bit confused if my reading is 40 but should be a lot lower. Will this explain why I'm exhausted so much? I've not lowered my dose for a long time


Yes exhausted is a good word. I've found that a thyroid person isn't just tired they get to the point that they stop and physically and/or mentality they can't go on. The reason I asked if you had recently had your medication lowered was to see if that was the cause of your TSH rising and would have suggested going back to the earlier dose.

After 6 weeks go back for a retest and post your results. Remember though that although your results may hopefully improve it takes a time for your body to catch up. There is also a list of symptoms on the site, print a couple off and fill one in now on your present symptoms and do another when you have been of the increased medication for 6 weeks. Hopefully it will show some improvement.


Thanks for your help. I'll post my results in 6 weeks


That's a very significant rise and I'd be wanting to understand what could have happened to do that. It did happen to me once although not that large a rise and my doctor didn't hesitate. He said, come and have another test next week and make sure you've taken all the tablets. Hmm! I had been going through an absent minded patch. The next test was back to normal!


Hi Claire you are clearly not converting your T4 to the active T3 hormone. By keep increasing your T4 it does it mean that you will reduce this very high TSH as the T4 is just sitting in the blood. Your doctor obviously does not understand the thyroid very well. I would suggest an adrenal saliva test from Genova labs to see your cortisol output and ask your doctor to prescribe some T3 to go with your T4.

Dr Thierry Hertoghe suggests a TSH if no higher than 2. See his site


Hi. Ive been told my cortisol levels are low. I was tested for Addisons Disease but it was borderline. My cortisol level was as low as 75 but I was put on hydrocortisone and it has now increased to 212. I am waiting on a referral to an endocrinologist. Do you think the thyroid and cortisol issues are linked? Thanks for your help


Most definitely without sufficient cortisol the T4 hormone cannot convert properly in the liver to T3 hormone. Also if T4 cannot convert this puts added stress on the adrenals


What do you mean by the doctor suggests a TSH if no higher than 2?


Dr Hertoghe has done extensive studies in Switzerland and he states the TSH should be no higher than 2. Please mail me at and I will gladly send it to you.


Ok thank you


Hi, here you are:

After working the whole week in Switzerland on a report of the

International Hormone Society on the TSH, T3 and T4 reference ranges,

I have sorted out all the studies that suggest that untreated patients

(in primary hypothyroidism, due to a weak thyroid gland) with a TSH

above 1.5 or 2.0 (reference 0.2-4.2) have cardiovascular

abnormalities, more obesity, depression, mortality, etc. enough data

to suggest a change of normal references to healthy references

(0.3-1.5 or 2.0). In case of secondary or tertiary hypothyroidism (due

to a weak secretion of TSH or TRH by respectively the pituitary gland

and hypothalamus), the TSH test itself is worthless. Likewise for T3

and T4, enough studies show that within the actual reference ranges

for T3 and T4, especially the lower half or lower third is correlated

with disease and higher mortality, enough to give serious arguments to

narrow considerably the reference range so that the tests help somewhat.

Of course the clinical condition of the patient (complaints and

physical signs) should predominate in the choice of the treatment as

they are the expression of what is really going on inside the cells.

There is data to support this view too.

Kindest regards

Dr Thierry Hertoghe

My TSH is about 0.04 at present and I'm fine, no signs of overstimulation. I take T4 50 mcgs and T443.75 mcgs, this seems the best ratio for me.

Take care


Thanks. It's all a bit confusing for me. At least I now know my thyroid is definitely not working correctly, this will help explain my extreme tiredness and also the issues with my cortisol levels. I definitely think an appointment with an endocrinologist is the way forward


Yes you really need to see someone but I hope they either recommend Natural Thyroid Hormone (some do allow it on the NHS but not many) or a combination of T4 and T3 and not just T4. T4 only stresses the adrenals if there isn't sufficient cortisol present.

Good luck!


Thanks again


Hello Bighen 37,

If I was you I would be asking myself why my thyroids meds were so clearly not working. A TSH of 40 is way too high and you must be feeling quite ill.

There are lots of reasons why thyroid meds might not work and I would suggest going back to the fundamentals as if these aren't right then no amount of meds be able to do their job.

It is important to take your pill around the same time, on an empty stomach with a glass of water, 1 hour before food, 2 hours before supplements and 4 hours before calcium, iron or vit D supplements.

People with thyroid issues often have vitamin deficiencies and it is recommended that you have tests for Vit B12, Vit D, folate and ferritin as optimum levels are required to ensure thyroid meds are absorbed.

Don't try dieting to lose weight as it won't work while your TSH is high and ensure there is fat and protein in your diet to provide essential nutrients and to aid with medication conversion.

If your dose changes, it can take the body 6 -8 weeks to adjust and symptoms may lag behind good biochemistry. The body will only accept small dose changes at one time.

I would ask your doctor for a referral to an endo as he will test all thyroids hormones giving a clearer picture.

I hope you feel better soon


Thank you for the reply and such good information.

I have never been told to take my thyroxine on an empty stomach!

I was advised to take folic acid back in March as I was low in Folate or ferritin, can't remember which.

I take vitamin B12 with calcium too.

I asked to be referred to an endocrinologist but the waiting list is six to twelve weeks.

I'm hoping to be seen sooner as I'm really struggling.

Is TSH 40 far too high and will explain my tiredness?


Absolutely. My TSH was 47 when I was diagnosed and I had felt terribly ill and exhausted. Looking back I don't know how my symptoms were missed for so long.

Endocrine clinics always have really long waiting lists. I have read some members advising that you can ring the endo's secretary and ask for a cancellation in order to get a quicker appointment but I don't know if it works.

Anyway, if you take your pill on an empty stomach now, it might start working.

Also remember thyroid problems can make you ill, leading to deficiencies which in turn stop thyroid meds working. Vitamin deficiencies must be recognised and supplemented adequately.

Hope you feel better soon,



Thank you


you should only ever increase by 25mcg or 50 mcg a day every 3 weeks so to go fr4om 125mcg to 200mcg a day is foolhardy

did your GP bother to check




Vit d3

because it may be they are low and no matter how much levo you take will not improve matters until your body is able to actually utilise the levo


No I'm afraid the doctor hasn't done much. My renal doctor picked up I need folic acid but I'm feeling a bit let down by my doctor.


Then you need to educate yourself and your GP or find one who knows what they are doing


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