Thyroid UK

How do you think the endo will play this?

Seeing my Endo this week. My latest results are Serum TSH 0.17mu/L (0.35-4.5); Serum free T4 9.2pmol/L (11.0-24.0); Serum free triiodothyronine 3.6pmol/L (3.9-6.8). I am following the usual trajectory of TSH low, and medics getting twitchy and reducing meds, even though T3and T4 in range. Since meds changed (now on T3 10mcgs and levo 50mcgs daily), T3 and T4 down and TSH up a bit. Feel undermedicated. Thoughts please.

Thanks so much.

11 Replies

Am I missing something TT - [Perhaps some more recent results]?

Your 'free' figures above for T4 and T3 are both under range -so being/feeling undermedicated is likely.


Sorry, didn't make it very clear. These are my most recent results, having been changed from 125mcgs levo only, to the combined Liothyronine 10mcgs with 50mcgs levo about 8 weeks ago. So since then, T3 and T4 levels have dropped, and TSH has marginally increased. Because the T3 was new, I think the Endo was kind of experimenting and I don't think prescribed a proper 'like for like dose' because my TSH was so low. Hopefully, he'll now see fit to bump up the dose a bit.



No cause to reduce meds I wouldn't think - not with FT4 and FT3 both below range.

Maybe that's the question you have to ask: "Why do you want to reduce my meds? What is the point o f having a reference range if I fall below it and you still want to reduce my meds?" That sort of thing. Put 'em on the spot.


This looks like possible secondary hypothyroidism, in which case the TSH test is useless. As your T4 and T3 are both low, your TSH should be high. I suspect, in this case, that your t4 and t3 are low because your TSH is low rather than the other way around. It looks, from your results, that your pituitary gland isn't producing enough TSH for some reason and this is resulting in low t4 and t3.

If this is indeed the case, your doctor needs to ignore your TSH and go purely by symptoms and free t4 and t3. Please do ask for this to be investigated if they insist on reducing your meds.

As has been said before, you need to argue your case. Your t4 and t3 are low so you need more medication. If they are going by your TSH and not looking at your t4 and t3 they are being negligent. It is dangerous to let your levels fall so low purely because your TSH is low. There is some other reason for your low TSH and it is certainly not too much thyroid hormone. TSH can be affected by many other things so should not be the only test for thyroid. T4 and T3 are far more important and accurate indicators of your actual thyroid status.

I hope this helps

Carolyn x

1 like

Thanks Carolyn. Very helpful. x


These results look like someone who has missed a dose just prior to a blood test, but usually has plenty of thyroid hormone on-board so their TSH is low.


Yes, I missed the morning Liothyronine, but nothing else. Thanks


So it was over 24hrs since you took a dose? if so the results make sense


Of Liothyronine, yes, but took Levo at around 11pm the night before


OK, therefore it looks like your Dr will increase your doses


Thanks everyone. Saw Endo today and Levo increased to 75 mcgs, plus continuing with 10mcgs Liothyronine, so we'll see how that goes!


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