What affects the TSH reading? : I wanted find out... - Thyroid UK

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What affects the TSH reading?

Quest2019 profile image
19 Replies

I wanted find out. Is it the T4? As I convert T4 quite well to T3. And I am in the higher range of both T4/T3.

So I thought if it was only the T4 that affects the TSH reading would it not make sense to lower the thyroxine and add a T3 med?

Not sure if I got this right? And for sure know doc may not agree..

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Quest2019
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19 Replies
greygoose profile image
greygoose

Both T4 and T3 can affect the TSH. But, reducing T4 and adding T3 would not raise the TSH, it would probably make it lower (if that's possible, don't know your TSH level). If that worked, they'd put us all on T3 whether we needed it or not, just to raise the TSH, as they're so obsessed with it!

TSH is a pituitary hormone. When the pituitary senses there is not enough thyroid hormone - T4 and T3 - in the blood, it increases it's output of TSH to stimulate the thyroid to make more hormone (Thyroid Stimulating Hormone). When it senses there is enough, it reduces its output. When it senses there's a decent level of T3, it reduces TSH to almost zero. Why? Because you don't need it. Why would the body waste energy on producing a hormone you don't need? :)

Quest2019 profile image
Quest2019 in reply to greygoose

Thank you. I always appreciate your input Grey Goose. I put another post up earlier. If you have a moment and are able to can you look at it and let me know your thoughts? Thanks again!

greygoose profile image
greygoose in reply to Quest2019

I'll have a look - but no guarantees I'll be able to help. :)

SassyMH profile image
SassyMH in reply to greygoose

Thank you for explaining this so clearly as Ive never understood the relevance of TSH. Is this related to a low TSH causing osteoporosis?

greygoose profile image
greygoose in reply to SassyMH

No, not at all. Low TSH does not cause osteoporosis. Long-term, over-range T3, such as you would get with Grave's - in which case the TSH would be suppressed as a result - might increase your risk of osteoporosis, as might long-term low T3. But TSH has nothing to do with it.

The TSH has two jobs: to stimulate the thyroid to make more hormone, and to stimulate conversion of T4 to T3. It does not affect bones

SassyMH profile image
SassyMH in reply to greygoose

Thank you.

Mickeydooley profile image
Mickeydooley in reply to greygoose

Sorry for butting in but do you or any of the admins have links to any research supporting this please? My endo is utterly convinced that TSH leads to bone and heart problems. I’ve looked online but no success so far. I’m going to see him again this week and would like to have something to show him. Thanks. X

london81 profile image
london81 in reply to Mickeydooley

i was thinking about this. i have always said to my endo and gp: i weight train and have a good healthy heart beat and blood pressure. i do not have oesteo or heart issues , and i am taking ndt which contains t3 which suppresses tsh. this was permitted by consultant endo . if the endo is so worried they should ask gp to do a heart and bone scan. put the onus back on them. but yes some science to prove our point would be great.!’ my understanding is that there isn’t much science because there is very little science on ndt or t3 but someone better informed than me might be able to confirm

Mickeydooley profile image
Mickeydooley in reply to london81

After my last appointment when he wanted to reduce my dose based on TSH I wrote to him to say how disappointed I was that he was reducing my dose because of a suppressed TSH and outlined again the improvements I’ve experienced. I told him that I still felt there was room for improvement in my energy levels etc and sent him details of my basal temperature, resting heart rate, blood pressure (all low) and pointed out that my t4 and t3 levels were well within range (32% and 62% respectively). He agreed to leave my dose as it was as long as I agreed to have a DEXA scan. I felt if I told him about my shaking and heart pounding he’d jump on that as evidence that I was over replaced. I’ve only ever had one suppressed TSH reading (last results end of November) so I doubt that any bone thinning would have occurred that quickly?!

london81 profile image
london81 in reply to Mickeydooley

shaking and heart pounding doesn’t sound good. i think there is info on dr lowes web page about how to spot over medication. whilst tsh isn’t relevant in my opinion when taking ndt or t3 symptoms of over medication are

it sounds like you have gathered really good data on your wider health ( basal and BP etc), it’s strange that you would have low indicators with shaking etc, maybe make a new post in the forum?

Mickeydooley profile image
Mickeydooley in reply to london81

It was suggested here that it may be to do with cortisol rather than thyroid. I bought a saliva test a while ago but with recent events just haven’t had time to do it yet. The instructions seem quite complicated. Probably aren’t really. Just my brain fog! I’m convinced that the shakes may be to do with blood sugar too. I’ve not been eating well or even often enough as I’ve been away from home and extremely busy and my appetite has been non existent. Happens to me when I’m stressed!

london81 profile image
london81 in reply to Mickeydooley

yes it sounds like you could do with testing cortisol & looking at stress reduction. i know it’s not easy i’ve been in same situation. good luck

Mickeydooley profile image
Mickeydooley in reply to london81

Thank you.

humanbean profile image
humanbean in reply to Mickeydooley

Sorry for butting in but do you or any of the admins have links to any research supporting this please?

I'm not an admin, but bone health crops up quite often on the forum, and the following threads have links within them that you might find useful :

healthunlocked.com/thyroidu...

healthunlocked.com/thyroidu...

healthunlocked.com/thyroidu...

healthunlocked.com/thyroidu...

endocrineweb.com/profession...

thyroidpatients.ca/2018/07/...

thyroidpatients.ca/category...

tiredthyroid.com/blog/2012/...

Mickeydooley profile image
Mickeydooley in reply to humanbean

Wow! Thanks! Much reading to do before my appointment! X

humanbean profile image
humanbean in reply to Mickeydooley

If you have a poke around in the links on this page you may find some other useful papers :

thyroiduk.org/tuk/research/...

Be careful with anything you show to an endo that the research paper you have is not ancient. I realised after posting that one of the links I gave you was published in 1992, so I deleted it.

Mickeydooley profile image
Mickeydooley in reply to humanbean

Yes I had a brief scan of some of the articles and realised some would not help my case! Thanks for all the info. X

in reply to Mickeydooley

ncbi.nlm.nih.gov/m/pubmed/1...

I think this is the main piece of research drs are referring to when talk about hearts, bones and tsh.

greygoose profile image
greygoose in reply to Mickeydooley

Have a look through this thread. You might find something useful:

healthunlocked.com/thyroidu...

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