My recent blood test showed my TSH level to be 0.6 miu/l and FT4 was 17.3 pmol/l. My GP has advised me to lower my levothyroxine from 125micrograms to 100 micrograms daily. I have been hypothyroid for 14 years now but just recently have been feeling anxious,agitated and stressed for no apparent reason, plus a sensation of not being able to cope with everyday matters. Could someone tell me if this is because of my current TSH and FT4 levels? Was I showing symptoms of being hyperthyroid? I have never seen an endocrinologist and one GP at my practice told me that FT4 and FT3 levels are not normally checked, only if TSH levels show concern. Now that I am taking less thyroxine,how soon should I start feeling like the old me again and should my GP request blood tests to check that I am not being overmedicated?My previous TSH levels were 0.6 in September 2023, 0.4 in March 23 and 0.7 in November 2022. No FT4 or FT3 levels were ever checked.
High FT4 level: My recent blood test showed my... - Thyroid UK
High FT4 level
What is the range for fT4? If it's the usual 12-22 then you are only mid range 53% and your symptoms could well be that you are under replaced and a small increase could be what you need rather than a reduction
Thank you for your reply,TiggerMe.
Oh dear. It's really not that simple. Your doctor hasn't got a clue, has he. TSH has nothing to do with symptoms. And once it gets below 1, it is a very bad indicator of thyroid status and should not be used to dose by.
I cannot comment on your FT4 because you haven't given the range. We always need to see the range because they vary from lab to lab.
I have been hypothyroid for 14 years now but just recently have been feeling anxious,agitated and stressed for no apparent reason, plus a sensation of not being able to cope with everyday matters.
That sounds more like under-medication than over. But your GP wouldn't know the difference if he's dosing by the TSH. But even dosing by the FT4 is bad because you have no idea what your FT3 is, and it's the T3 that causes symptoms. You need to know how well your body is converting that T4 to T3, and if you still have symptoms, and your FT4 is high on only 125 mcg levo, you probably aren't converting very well. But, you have to have the FT4 and FT3 tested at the same time to be able to see how well you convert. Your GP wouldn't know that, either.
Now that I am taking less thyroxine,how soon should I start feeling like the old me again and should my GP request blood tests to check that I am not being overmedicated?
Well, that depends on whether you actually needed to reduce your levo. If you didn't, then you could feel worse.
Your GP should retest six weeks after any change in dose - not just to see if you're over-medicated but to see if you're under-medicated. However, the TSH could be at the same level in either scenario because, as I said, at that level, it is a bad indicator of thyroid status.
So, if I were you, I'd do a private test so that you can see the complete picture. Details or private testing companies here:
thyroiduk.org/testing/priva...
Thank you for your advice,Greygoose. Can I insist now that my GP refers me to an endrocrinologist; I have never ever seen one. I have often wondered why I was given thyroxine in the first place but just accepted my doctor's advice.
No, you can't really insist on anything. And, even if the GP agreed, the endo could refuse to see you on the grounds that your FT4 is in-range - if it is in-range, but you still haven't given the range. 
And, as I said, that might not be the right course of action, anyway, because endos don't know much about thyroid, either. They are mainly diabetes specialists.
As to why you were given levo in the first place, do you have your blood test results for before you started it? They would tell you why.
My blood tests in January 2010 showed TSH to be 7.8miu/l and Serum T4 to be 8pmol/l. The range for Serum free T4 at present is7.9 to 14.4 .My current free T4 is 17.3 pmol/l.Thank you for your help,Greygoose.
OK, so with a TSH of over 7, you were pretty hypo and did need to start levo. Now, your FT4 is too high, but remains to be seen how high your FT3 is, because that's the most important number.
Have you had your antibodies tested? If not, they need to be.
Then I shall ask GP to request these tests.Why do they not test for FT3 if other results are not in range?
a) because they do not understand the importance of testing T3 - most doctors don't even know what it is! b) cost-cutting! They will do loads of useless tests and are very hot on cholesterol testing, even though they know nothing about it but are intent on prescibing statins to as many people as possible, but the wouldn't understand the results of an FT3 test if it got up and bit them! So, they cut it out to save money to test more cholesterol levels without a clue about the connection!
Sorry, rant over. 
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