Thyroid UK
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Help needed - conversion issue?

Any help would be greatly received on my thyroid levels. History is mild hypo, thyroxin 50mg from summer 2015, raised Sep 2016 to 75mg (they say TSH should get to 2.0). Reason for increase was excessive blood loss and highly frequent periods, age 42. Ferritin 9. Just had bloods retested privately and looks like T4 has responded to the levothyroxin, but T3 remained the same after a year and half. It's not below range, but towards the low end of the range. I am still very lethargic, and losing weight is hard (does your T3 level need to be higher to lose weight?). I'm back on the pill and on iron to help with the iron stores.

My levels all listed below. Question is should t3 have increased on levothyroxin? Should I have a mixed treatment adding t3 in? Are docs likely to agree? What are the optimal levels for TSH ft4 and ft3 on levo? How does reverse t3 come into it all! Should I test this privately?


Nov 16. 2.45

Jun 16. 2.46

Feb 16 2.22

May 15 2.9

Jun 15. 3.21

T4 total

Nov 16. 96.1. (64-142)


Nov 16. 4.23 (3.1-6.8)

Jun 15. 4.3


Nov 16. 15.26 (12-22)

Jun 15. 11.7

6 Replies

Welcome to the forum, Sarah5-5.

I think you are under medicated rather than having poor conversion. Increasing dose will raise FT4 and FT3 and lower TSH.

The goal of Levothyroxine is to restore the patient to euthyroid status. For most patients that will be when TSH is 1.0 or lower with FT4 in the upper range. FT4 needs to be in the upper range in order that sufficient T3 is converted. Read Treatment Options in Email if you would like a copy of the Pulse article to show your GP.

Make sure to take iron 4 hours away from Levothyroxine.

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Thank you so much, it's really hard to get to the bottom of what your levels should be "ideally". How high do ft3 levels need to be to feel normal, have energy, stop gaining weight etc? I do now take my iron in the evening and levo in the morning, but only since September. How much levo would you expect I might need to have an impact on the ft3?



Dose increases are usually in 25mcg increments.

It's very individual but most people will feel well with FT3 >5.5. I'm fine with FT3 >4.5.

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Thank you so much. If my ft3 doesn't improve with thyroxin increments, and I still have symptoms, should I be asking for t3 addition? Should I get my reverse t3 tested privately? As doctors don't prescribe t3 where do you get trusted t3 from? I would be worried buying abroad? Or can you simply ask GP to write a private prescription? Is that then easy to fulfil in uk chemists? My bloods get tested so rarely, think it could be many months before I get that t3 up!



Your GP should test blood levels 6-8 weeks after a dose adjustment. Symptoms should improve when you are optimally medicated but it can take 2-3 months after levels are good for symptoms to resolve.

Most members without NHS prescription order T3 online. T3 will cost £258+ for 28 x 20mcg with private prescription. You can post a question asking members to recommend via private message where to obtain T3.

1 like

Thanks clutter. Oddly I didn't get retested for a whole year after going on thyroxine!


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