Suppressed TSH 🤷🏼‍♀️

[MissFG]

I reassured my GP on Friday that my suppressed TSH & low FT4 was expected as I’m on T3 only. I’m sure my Endo might have said this and that’s where I got it from.

Was I correct? What does suppressed TSH mean and does it matter?

[Jazzw]

You were absolutely correct, yes.

TSH tends to be suppressed even on quite low amounts of liothyronine. That’s because TSH is a pituitary hormone, not a thyroid hormone. It’s created to prompt the thyroid to make thyroid hormones when the pituitary gland senses they are low. However, when the cells have plenty of thyroid hormone available, there’s no need to prompt the thyroid - so the level will be very low and suppressed.

So after diagnosis of hypothyroid and the commencement of thyroid hormone replacement therapy, TSH isn’t really all that helpful at all. FT3 is really about the only reading that’s any use when on T3 only.

[MissFG in reply to Jazzw]

Thank you I thought that was correct but wasn’t sure the basis of it.

Such a shame our GP’s don’t know more about hypothyroidism and it’s treatment

[serenfach]

When they start on me about a low TSH, I always say "oh good, it is a block and replace, so that is a good result". They stop nagging as they dont know this is not true.

[EleanorM-G]

You are right!

“Suppressed”, just means it’s very low/far below the “normal range”.