Thyroid UK
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Pushing FT4/FT3 into the upper ranges

This Friday I am going to see my Endo, with my brain... now that I am on LT3 :-)

My latest results in March 2017 were TSH 1.5 mu/L [0.4-5.5], FT3 10.2 pmol/L [11-26] and FT3 3.4pmol/L [3-6]. I was on TEVA LT4 10ml (50mcg) , but I have upped that to 13ml (65mcg) and I have kept LT3 at Sigma Pharma 5mcg TDS. I am still very fatigued, pushing through the treacle, and would like FT4/FT3 to be in the upper ranges.

I am DIO2 gene heterozygous.

Does anyone have any literature/links to support FT4/FT3 needing to be in the upper ranges, as my Endo is happy with them being bottom of the range?

I have got Dr A. Toft Pulse Magazine article on TSH levels.

Thanks lovely people :-)

4 Replies


You may still be under-medicated and need to increase your meds a little but don't become fixated upon high in-range results.

Results are only an indication of how much you have in your blood stream and not what is actually working, and sometimes it is all the other factors that need improving to make the meds actually work for you.

It appears true that many on this forum need levels high in-range in order to function well and I would attribute that to how ill these poor people have been allowed to become .... but I have found as my health has improved I have managed to reduce meds significantly.

I suffered psychosis from thyroid meds and have never been allowed to go high in range. I would also be too scared to try. I have many MTHFR issues and iron overload problems (Heamochromotosis) but concentrating on iron, nutrients, adrenals problems and diet has allowed thyroid meds to work well for me.


Psychosis? From being too high in T4 or T3 or both? Which med were you taking?

Interesting about reducing your dose over time. I'm finding the same.


Hi there- do you mean that- like me- you have a mutation on the gene that means you are unable to efffectively convert T4 to T3? If so, I feel terrible on more than 25 mg levothyroxine. My doc asked me to ' up ' my t4 because my blood tests were 'strange'. That was because I was on 25 mg t4 and 3 doses per day of 20 mg t3. I have felt dreadful with headaches and brain fog etc since upping my t4 to 75 mg. Today I have reverted back to 25 mg levothyroxin and trying 2.5 doses of t3. I can't comment on fatigue as I have ME/CFS. I recommend Paul Robinson's book 'recovery with t3.

Best wishes

1 like

Hi chrisknott, thanks for your reply. My faulty DIO 2 gene means I have T4 to T3 conversion issue. Having LT3 has helped me get my brain back after years of brain fog.

I am wondering whether LT3 only might be the way forward, but until then I want push into the upper ranges, if I feel ok of course, to be able to attain some euthryoid state on LT4/LT3 combo. I am going to get full TFT done privately so I know what rT3 and TT4 are doing. A lot of LT4 makes me feel nauseous.

The Endo seems to be happy "tickling the situation" to get me just in range and has done so for 2 years and its not touch my fatigue. It's difficult to know what to do with the Endo.

I have been diagnosed CFS. Got my magic 5 Vitamins/Minerals well in range and I am looking at root causes, as I am Hashimotos, now with AIP diet etc.

What a journey we are on! :-(


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