This paper demonstrates how TSH changes lag well behind changes in FT4/3 levels. The longer the dwell time of a particular set of FT4 and FT3 concentrations the longer the lag in TSH response. Useful to provide evidence that TSH is not a credible test if applied wrongly at the wrong time.
A Review of the Phenomenon of Hysteresis in the Hypothalamus–Pituitary–Thyroid Axis
Melvin Khee-Shing Leow
Review
Published on 14 June 2016
Front. Endocrinol. doi: 10.3389/fendo.2016.00064
On a quick first glance looks very interesting and helpful. Documenting what we all know - that TSH is a very unreliable guide to treatment.
Thank you
I found this when I reduced my thyroxine - T4 moved but TSH remained the same despite two drops in dose. Why, oh why don't doctors and endocrinologists know this.
Karen
Can i ask an 'idiot' question ?
The examples used in this are called 'clinical vignette's'........ how is this different from 'case study' ?
Are they actual results from real cases or more like ideal examples .
The Autoimmune Hypo patient's TFT's seem much 'better behaved' than i'm used to seeing in real life on here !
In Singapore, the medics are very well educated in thyroidology matters and many others. I suppose that given the number of patients those who didn't tolerate T4 only well might not show up. The examples really are snapshots of a general reality as shown by individuals.
thankyou.
Just to be 'awkward' , (i've never aspired to be 'normal', and don't want to start now )
I once tested the 'TSH can be slow to recover from suppression' thing on myself.
I'd had TSH of below 0.05 for 6 yrs (on Levo ) ,
I then withdrew Levo totally for 14 days and tested...... TSH came back at 7.897 !
which satisfied my curiosity as to whether my TSH still 'worked'. (as long as you kick it hard enough)
NOT recommending this experiment to anyone else..... feels awful.
I have experienced the opposite 
My doctor took me off my 3 grains of NDT, 5 weeks later I am in a hospital ward feeling like dying, TSH came back at 0.009 and ft3 ft4 low! It took months for me to be able to leave my apartment
confirming my current belief that TSH does not read books on what TSH is supposed to do....... and is in fact controlled by mischievous blue pixies, who's only pleasure in life is to try and make doctors pull 'confused' face.
That was my experience too, Hidden . I didn’t let it go as far as 5 weeks thank goodness—think it was about 10 days!—but my TSH stayed stubbornly at 0.000 something while my FT4 and FT3 fell through the floor.
Scared me a bit—I’d been kidding myself that if there was ever a time when I couldn’t get hold of NDT I’d be able to muddle through until a GP put me on Levo. Now I’m not so sure...
You've had an awful experience due to the inability of the medical professionals to know very much about what is the purpose of thyroid hormones.
Unfortunately 
3 years later still sick, can't find the dose that suits me and have all options available!
It's time gp's learned not to mess with doses in patient's who feel well......... cos it's not just a matter of 'put it back' how it was before , even if you return to the previous dose.
Sounds like some people never get back to where they were.
I'm getting concerned this is what's happened to me following 3 recent dose reductions by the GP m which later had to be put back up after they made me very unwell/ undermedicated / constipated... but we'll see.
'First do no harm' ? if only that were true.
I am sorry to hear this happened to you too
I wish I didn't stop my meds back then, now I know better. I was overmedicated a bit at the time, but instead of tweaking the dose, I was told drop 1 grain, 2 grains, all grains.
I still believe it is possible to be on same on similar dose, but it takes extra time to get this to work again, to get all the cells to wake up again as they did have to shut down for business!
That's why it's so important that they understand the TSH lag thing.
I think i was a smidge overmedicated too, but when the re-test TSH still hasn't risen in response they go mental and want to reduce again and again.
At the time i thought it must be wrong to need another reduction, but it's hard to totally ignore your GP telling you you'll die, and my aged Auntie on Levo did have a nasty Stroke. So after a while i did as i was told.
Wont be doing that anymore now though.
I'm afraid he's created a monster
It really is, I was also told I will die, that I will be in ICU in their hospital, having a thyroid storm😳then another GP I went to said that I should be happy I am losing weight (I believe that was from stress of it all).
Haha, yes, welcome to the club Hashimonster!
Thank you diogenes
How quickly does tsh rise? 
What does Tsh respond to?
TSH level and over active thyroid
Isolated thyroid-stimulating hormone (TSH) deficiency?
