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T3 advice needed

I have been hypothyroid for 17 years, post thyroid cancer.

I was stable on 200mcg for 10 years until recently moving House and changing my GP.

I was advised not to eat or have caffeine for at least half an hour after taking my medication which I did. I felt great but my T4 levels rose.

I have been told to reduce my dose and having blood tests to check it regularly.

14th June T4 34.6 (range 10-23) taking 175mcg

3rd August T4 27.9 (range 10-23) taking 175 x3 days and 150 x 4 days.

20th October T4 30.1 (range 10-23)?taking 150mcg.

T3 4.5 (range 3.1-6.8)

I asked for my T3 to be checked as I was worrying about beginning to feel unwell. My GP doesn’t do this ‘normally’. I also pointed out that my T4 blood test had gone up when my medication had gone down, but GP didn’t seem concerned. Asked to reduce to 125mcg.

I’ve been taking 125mcg for 2 weeks and feel awful. I’m now off work sick as I’m exhausted, difficulty concentrating etc. Usual hypo type symptoms.

I’m waiting for a call from my GP to discuss what happens next.

I’m interested to see if taking T3 with my T4 might help, and also keep GP happy with my lab results. I’m assuming now I feel awful my Next T4 test will show within the range!

But if he won’t prescribe it, where could I get it from please?

13 Replies

Hello LindsLou

You should be on what made you well and physically able to function. Ie the 200mcg you were on previously.

Is your supplements and vitamin intake optimal? Do you know which ones and strength to take?

Is he/she testing T3 - you didn’t say. If not Blue horizon or Medichecks do (thyroid 11 and BH - is the one that is of similar price) mC do discounts most Thursdays.

High quality and adequate amounts vits and supps will really compliment your T4.

Bloods best 6 weeks apart. And miss the dose the morning of the test and take it straight after. This gives a truer picture of your TSH. And first time in the morning - literally the first appointment for bloods. Get there extra early if it’s first come first serve.

It’s suggested an hour re food and fluid intake as certain things affect absorption.



Lindslou was dangerously overmedicated on 175mcg. FT4 needs to be mildly over range max or atrial fibrillation can develop.

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Thank you Clutter. I re read the results earlier and just now. Don’t know how I missed that. But just taken my fist tea of the day. Note to self do not comment until contact lenses in and caffeine in situ.

Thanks again for correcting me so quickly.

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Would you care to elaborate on that, Clutter? First time it's been mentioned that over-range FT4 affects hearts.

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'Measurements of total T3 and free T3 are not available in the RS and therefore the association between these thyroid function markers and AF could not be assessed.'

Nor does it say whether they are talking about exogenous or endogenous T4. I think it was diogenes that said that there are not the same risks associated with high levels caused by over-medication, as there are when caused by over-production by the thyroid gland.

So, I shall take that study with a pinch of salt.

Thank you for posting.


Never had my vits and supps checked, I will sort myself a private blood test to see where I am.

But I did Know about missing the dose before a blood test, have been living proof that this is essential!

T3 will be tested again next time by my GP because I’ve asked for it.

TSH levels are checked but I haven’t been told what they are with this new GP, but will ask next time.

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You were overmedicated to have FT4 so much above range. It's okay to have it slightly over range but too much is not good for the heart. Read Treatment Options in thyroiduk.org.uk/tuk/about_... Email dionne.fulcher @thyroiduk.org if you would like a copy of the Pulse article to show your GP.

You are a poor converter to have FT4 >30 and FT3 only 4.5 and FT3 will have dropped after the reduction to 125mcg. It would be better if your GP could add Liothyronine (T3) to Levothyroxine to raise FT3. You GP may need to refer you to endocrinology for Liothyronine to be prescribed. That will take weeks/months so buying online and self medicating may be helpful.

Start by adding a quarter of a 25mcg T3 tablet (6.25mcg) to your current Levothyroxine dose. If necessary, add a second 6.25mcg dose at bedtime after 2 weeks. Hold at 12.5mcg for 6 weeks and have a thyroid function test including FT3 before increasing further.


Do you allow a 24 hour gap between your last dose of levothyroxine and the blood test which should be a fasting blood test (you can drink water) and you take levo after the test?


Well I skip the morning dose. Not sure if it’s exactly 24 hours. I was attempting a fasting window diet during the period of my last blood test and I think this skewed the results. I’m now eating normally again.

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Was it the earliest possible appointment? (just trying to figure out why :) )


It’s drop in, I got there 1/2 hour after I woke up! Somewhere between 8.30 and 9am. I know it’s weird. I think I should be re-tested on 150mcg, in case it was an anomaly or dare I say ‘mistake’ by the hospital!


Go by your instinct, I think because mistakes can happen in the best of places. If result was the same then you could look into it further.

I am assuming you didn't have any of the following:


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