Thyroid UK
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Adding T4 to T3

Hi all, I was on 5 grains of Naturethroid but had to get off NDT to treat high night time cortisol and low iron. I am now on T3 alone, for almost 4 weeks, but my GP has prescribed Levothyroxine because he said my Free T4 was too low. I was just going to ask, to those on combination T4/T3, how do I add Levo to T3? I am currently down back to 15mcg of T3 a day as I realised I had made some mistakes and started on a very high dose, but I will be raising every week by 10mcg. I am scheduled for more blood tests in about 4 weeks time and am also due for dental surgery in the next few weeks so am hoping to get things under control by then. Thanks.

8 Replies

If you are on T3 only you will have low FT4. Have you considered joining the FB group Recovering with T3 I think it is called, as they can help if you want to carry on just using T3?


Thanks Blue, I will look up the group. I plan to just take T3 until my low Iron and cortisol issues are sorted and then go back to Nature-Throid cause I felt so much better on it and my hair even started growing back really thick. But for now, I need to have surgery to extract an impacted tooth and GP insists my levels should be within what they consider normal range and so is insisting on T4.



Can you post the thyroid results and ranges (figures in brackets after results) and say how much T3 you were taking when tested?

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Hi Clutter, thanks, I've just seen your response, Please see below:

New results from 12th July - I was on 50mcg T3 a day but the day before the bloods I only took the morning dose which was of 25mcg.

TSH - 0.01 range 0.30 - 4.20

Free T4 - 5.2 range 9.00-19.00

Free T3 - 2.7 range 2.60 -5.70

Below are my results from before (11 July, 2016) when I was on 5 grains of Nature-Throid.

TSH - 0.01

Free T4 - 16.6

Free T3 - 8.1

Thank you.



You were over medicated on 5 grains NatureThroid if you left 24 hours between last dose and blood draw because FT3 was over range.

You've skewed the results on T3 by only taking half the dose the day before you tested. It would have been sufficient to leave 12 hours from last dose of T3. As FT3 is bottom of range it is clear that 25mcg is insufficient.

How much Levothyroxine has your GP prescribed?


Thanks Clutter, my GP has put me on 50mcg Levothyroxine per day.

With the T3, I was supposed to start on 10 to 15mcg a day but I thought the 25mcg tablet was 5mcg (I had been off the naturethroid for a week before I started T3 so I think this added to the confusion). So I went straight to 50mcg T3 instead of increasing slowly.



You didn't need to increase T3 slowly because you were already taking 45mcg T3 in 5 grains NDT. 50mcg Levothyroxine plus 50mcg T3 isn't likely to deliver great FT4 but should deliver reasonably good FT3. You can take the Levothyroxine and T3 together.


Okay, I see, gosh, its all so confusing and thanks again Clutter. I will add T4 and see how combination of the two works. Have a good evening.


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