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Thyroid UK
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Does medication screw up the thyroid hormones if prematurely treating a euthyroid syndrome?

I wonder if I had prematurely gone on thyroid hormone medication. The first TSH test I got done was back in 2013 after my first and worst bout of tonsillitis. Didn't get the full panel done though I wish I did, I was 5.30 (barely in range, out of top range 5.50). By the time I saw the ENT months later I was cleared as fine though have had recurrent tonsillitis ever since, finally will have a tonsillectomy done next month.

Anyways, after that first test, a few months later I got a full test done and TSH was 4.20 (0.30 - 5.50), T4 36% in range, T3 24% in range, TPOab in range (and in range ever since, TGab too). But I jumped the boat and went on NDT after seeing a naturopath. Fews month later TSH was suppressed and T4/T3 were just above mid-range.

But years later, last year, (I was refilling the same script for years lol) my test showed suppressed TSH but T4/T3 in third of range. GP took me off medication full stop (dumb idea, gained much weight, should've transitioned down).

Couple months later, off meds after years on NDT, T4 is 36%, T3 dipped just below range, TSH is 2.5. Doctor said T3 "is just below range you're fine." I disagreed but went along to address my low B12 and Vitamin D deficiency and see its effect.

4 months later, as vitamins improved, TSH was same around 2.5, T4 12% in range, T3 37% in range. I convinced the doctor to start me on Synthroid.

Now check this out, compared to that 12% T4 and 37% T3. After being put on Synthroid, T4/T3 fluctuated around third in range. TSH around 2. On 75mg T3 matched the 37%, T4 38%.

100mg T4 shot to 79%, T3 drops to 31%, TSH drops to 0.57. I felt more frequent bowels so dropped to 88mcg, after 4 weeks, TSH 0.66, but T4 43%, T3 32.5%.

Note that while T4 seemed to rise with Synthroid, T3 had actually been lower than the 37% (though T4 was 12% at that time) when I was off thyroid hormones for 6 months after years on NDT. I guess I'll find out what happens to my body after the tonsillectomy, if the recurrent tonsillitis has been affecting my body or it's just an annoyance in my throat. But I wonder that if I actually had euthyroid syndrome and prematurely went on thyroid hormones, if it screwed me up and now I need to take it for the rest of my life.

3 Replies

I don't think so. I don't think it works like that. Your thyroid was struggling and couldn't respond to the signals your pituitary gland was sending to it. It should be able to up or lower production according to that signal. A healthy thyroid grows and shrinks to meet requirements over the years - so if it had been fine, when you came off replacement hormones it should have been able to rise to the task, if you see what I mean. The research I've read suggests that it takes about 6 weeks for a healthy thyroid to get itself back to normal after its owner comes off thyroid replacement hormone it didn't need. That research is around because of the huge numbers of people who take thyroid hormones even though they're perfectly healthy to speed weight loss or cut muscle (not a good idea for many other reasons, but there you go).

The analogy I use is what happens when a woman takes the contraceptive pill. The hormones in it replace those normally produced by the body. Now, if taking the pill left all women chronically infertile when they stopped taking it, there might be a case for thinking that taking replacement hormones messes up the body's ability to do it by itself. But that doesn't seem to be the case - the body seems to quite happily take over the production of hormones when coming off it.


Totally agree with Jazzw. You wouldn't have 'screwed up' your thyroid in any way. And, if you have to take thyroid hormone for the rest of your life, it's because your thyroid isn't up to producing enough itself - and hasn't been for quite a while, by the sound of it. :)


Well that is definitely something positive to think about. If, by chance, after the tonsillectomy the reason for the lowered thyroid hormones is cleared, I assume that over the next few weeks I'd experience hyper symptoms then. And slowly transition off of the Synthroid.

A side note, whether or not there is a problem with my thyroid, the damn doctor should not have taken me off of 125mg NDT cold turkey. Was a terrible idea, at the very least should've transitioned me off to run his "experiment." As the lab rat I gained so much more weight, and well it's much easier to gain than lose.


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