T3 and T4 results interpretation: I posted... - Thyroid UK

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T3 and T4 results interpretation


I posted recently where I was considering self medicating as I have so many symptoms on Levothyroxine meds.

I've had my levels checked by Medicheck and the results are:


T4 - 134.4 nmol/L (59-154)


T3 - 1.4 nmol/L (1.3 - 3.1)

* FT4 - 22.99pmol/L (12.00 - 22.00)

* TSH was 1.05 (0.3 - 5.0)

Seeing the GP last week I suggested how I had felt a little better when my TSH was lower that it is currently, but of course within range. He agreed to allow me to add 25mcg to the 100mcg I already take with a blood test in January to ensure it is still within range. He said if there is no major improvement, or the TSH is out of range then he would not allow me to continue with the extra 25mcg.

I would be grateful for any feedback on this.

Thank you in advance.

12 Replies

craftyang Is that FT3? if so your conversion is very poor and I would say you don't need an increase in Levo, you need the addition of T3 (my opinion only, I'm not medically trained).

Thank you SeasideSusie. I had these tests as my Gp has never ordered them and refused to do so, with the exception of T4 once several years ago. I have read so much about people not converting well, I wanted to see if it was the case for me. I showed these results to my GP and he said that the only important measurement was the TSH and I should pay no attention to T3 etc as it tells us very little...I managed to remain calm while he said this!! He also said that long term use of additional T3 has shown to cause an increase in cardiac problems. I have no idea if this is true but I'm pretty sure I would have read that somewhere on this forum at some point if it were.

SeasideSusieAdministrator in reply to craftyang

craftyang So we can put your GP firmly on the top of the useless doctor pile because that is clearly where he belongs. He has no idea. The TSH is important as a diagnostic tool. Once diagnosed hypo and on medication the most important test is the FT3 as T3 is the active hormone that every cell in our body needs, unfortunately it is rarely done and most doctors only dose by TSH regardless of a patient still being symptomatic (which they usually say is nothing to do with the thyroid and must be something else, hence many people end up on antidepressants, stations, etc)

Waterloo? Or Victoria? lol

Sorry, couldn't resist! I take it you mean statins. :)

SeasideSusieAdministrator in reply to greygoose

LOL Greygoose - I normally check for silly autocorrects, definitely missed that one :D

Oh, they can easily slip through! I always check for spelling mistakes, but sometimes I find them years later! lol

craftyang your t3 is barely touching the bottom end of the range and your t4 is high in range - that tells you the levo isn't doing much for you aside from raising your t4. You may be one of these folk who does better on t3 alone. In any case it's no wonder you don't feel well where you are.

It's true, if you're taking too much t3 it can damage your heart and bones, but you're not asking to take too much, ideally you'd like to be taking the right amount. This argument is a red herring; the gp might as well apply it to levo too, and any drug or hormone supplement really.

Thanks for your reply puncturedbicycle and very well said- that's exactly what my husband and I said to one another later that day!

I have been considering adding T3 to the Levo I'm currently taking. Would it be correct to stop 25mcg of the 125 I'm currently taking and introduce T3 in its place? From what I've read on this site, taking much smaller doses of T3 and increasing gradually, monitoring results seems to be the method most commonly used. Would you agree?

The usual approach is to reduce levo by 50mcg and add 10 t3 (it's thought that 30-50 levo = 10 t3). Your t3 is on the floor, so you will almost certainly feel much better quite soon, and after the levo has time to leave your system you may want to try doing this again (reducing levo by another 50 and adding in 10 t3).

I'm sure under the circumstances (having such poor conversion) you could do this a bit quicker but it is generally thought best to add small amounts of t3 slowly. I hope someone w more experience in conversion issues can add their thoughts. As Marz has said below you may see some improvement when your ferritin improves so it's possibly still wise to move slowly.

Good luck! Keep us updated!

So the T4 can convert well into T3, you need good levels of Ferritin - Folate - B12 - VitD. Optimal levels and not bumping along the bottom of the range. Have you had yours tested and do you have the results ?

craftyang in reply to Marz

B12 was low and after your advice regarding the best supplements this is now over the top of the range and I'm aware that this will not cause problems. My ferritin is almost at the bottom of the range and although I was already supplementing I have now changed the source as per recommendations on this site. My folate is in the centre of range but I've never had my vit D tested.

Marz in reply to craftyang

Sounds as if lots of good things are happening for you. Maybe when the Ferritin improves - so will the conversion of T4 into T3.

Good luck with the T3 😊

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