Thyroid UK
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Underactive thyroid

I was diagnosed by endocrinologist who was seeing me for a prolactinoma (pituitary tumour) and he wrote to my gp to say I had low t4 levels.

I have been on levothyroxine for over a year now. I am on dosage 150 per day.

Each time the dr requests a full test the lab Denys it so he just kept uppering the dose. I then had a full test due to heavy period problems. Another GP rang me to say my T4 is now in the high end of normal and my TSH is running low (which used to be normal)

I am feeling rubbish. I have severe mood swings too which the go has put me on mood stabilisers and anti depressants. Should I go private to check my levels and had anyone got any advice about doing so.

Many Thanks

7 Replies

Cally36 I think the first thing you should do is ask for a print out of your results and let's see what's going on. You are legally entitled to them under the Data Protection Act. Post them on the forum, with reference ranges, for comment.

If there are any other tests that would be useful then members will advise and you can always do a private test then.

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Thank you SeasideSusie i will ask for the print out and put them on here asap.


Hi Cally, we usually want our FT4 level to be high in the range and this usually reduces your TSH. The important part is whether your FT3 is high enough. This is the active hormone while FT4 is merely in storage until converted to T3. Sometimes that does not happen efficiently and some do better taking natural desiccated hormone which includes some T3. If your FT3 is low in the range, it would explain what is going on. Either you are not on a high enough dose of T4 or your T4 is not converting due to a cortisol or ferritin issue.

I don't know how the tumour effects your thyroid but your TSH should be low, around 1 or so. Antidepressants interfere with your thyroid treatment and would be better to correct the treatment instead.

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Thank you for your reply Heloise I am seeing the doctor on Friday and will ask for a print out of my last blood test


I have a pituitary adenoma, too, but had to self-diagnose then treat myself for secondary hypothyroidism. From what I can gather, the normal thyroid tests aren't always helpful, as they should be looking at thyrotropin releasing hormone (TRH) rather than TSH. We don't have the usual straightforward blood test results for hypo, though definitely the same symptoms. I'm unable to find the chart for this information, sorry. The endos seem clueless to act on symptoms, & GPs worse, my last one diagnosed FM instead of hypothyroid.

You could be like a lot of people, & not take well to T4. I went straight to NDT, then tried T3, so have no experience of taking T4 only. T3 can be useful to treat depression, & was once prescribed for this. It's also good to make sure your nutrient levels are high so that the thyroid hormones can convert to the T3 all our cells need.

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Thank you BadHare i am just enquiring to see a private consultant and then get all areas checked again and pay.

I am please you flagged this up as I too belief my adanoma is masking the TSH levels.

I too have been diagnosed by a gp and a rheumatologist That I have fm but then the endo said my t4 was low so it was all change then.

I will keep you all posted.

Thank you again for the support and time to reply.

1 like

You're welcome!

Do make sure you get a TUK recommended consultant, as not all private ones seem to know what they're doing, either. The symptoms of FM & hypothyroidism are almost identical, but pharmaceutical companies make more money from FM as so many drugs are prescribed that don't work, compared to T3 which does.

Good luck!


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