So disappointed about recent test results - Thyroid UK

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So disappointed about recent test results

This thyroid stuff is so confusing to me.

I was introduced t4 6 weeks ago at 50mcg, then increased to 75mcg two weeks ago.

I was taking just t3 prior (18mcg)

Been on lower dose of t3 (15mcg) for two weeks with the increased t4 dose of 75mcg and my blood test results are exactly the same as 6 weeks ago except tsh had gone down d/t introducing t4 with my t3.

My goal is to get off t3 because I plan to become pregnant and appropriate t4 levels are necessary.

Tsh .7 (.5-4.5)

Free t4 .8 (.8-1.8)

Free t3 2.6 (2.3-4.2)

Why after six weeks have my free t4 and free t3 levels hardly changed?

11 Replies

Has the hospital insisted that you drop the T3 and start on T4? It's not an area I know anything about but I have seen posts of would be and pregnant ladies taking NDT and getting hospital support. So asking the question so that someone may give you better advice on your reply from their experience. I hope things go well for you.


Testing just two weeks after dose change is too soon

You will need test 6-8 weeks after increase to 75mcg

Then re-evaluate

Are you checking your vitamins too

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T3 and T4 are both different forms of thyroid hormone, so when stating a dose it's clearer to say how much T4 and how much T3 you are on, as both end up added to the same pile once they get into your body and start getting used up in your cells. Looks like you've been on:

Prior to 6 weeks: 18mcg of T3

6 weeks ago: 50mcg T4 & 18mcg T3

2 weeks ago: 75mcg T4 & 15 mcg T3

I can't tell from you post whether at the 6 week point you were taking 50mcg of T4 and 18mcg T3 at the same time, or whether you dropped the T3 altogether at that point?

There are a couple of things wrong with this picture. The first is that to get a good blood test you need to hold on the same dose for about 6 weeks. You also need to leave a 24hr gap between your last dose and the blood test.

Another problem is that by adding T4 to the same amount of T3 you were already taking you've had a large dose increase. T4 is turned into T3 inside your body, so by adding T4 you're effectively adding even more T3. T3 as a tablet is about 4x as potent as T4. This means 10mcg of T3 is roughly equivalent to 40mcg of T4. I say roughly, because these things are handled differently by the body, and everyone's body is different, so you can only make a rough estimate.

So by adding 50mcg of T4 you were adding in about 70% of what you're already taking, when you upped that to 75 mcg, that about doubled the amount of hormone you were taking over a 6 week period. You would expect your numbers to improve quite a bit with such an increase. But also your body may just be very shocked you've increased by so much. Usually it's suggested to increase by about 25mcg of T4 at a time. Or if you want to swap out some of your T3 to add T4, you need to reduce the T3 by about the same strength as you add T4. So if you want to add 50mcg of T4, reduce by about 12mcg of T3.

However, looking at your blood tests you are due for an increase anyway. Both your freeT4 and freeT3 are right at the bottom of the range. Ideally you want them to be in the top quarter of the range. If I were you I'd stick with what you're currently taking, and get a new blood test when you've been on it for 6 weeks. I agree with others that its also an idea to shop around for a doctor who will support you on T4 and T3 combination in pregnancy. You're on T3 for a reason - because many people don't feel well on T4 only. You may be one of those people, and you'll end up on a wild goose chase trying to get back to a dose that makes you feel well.


Thank you for the explanation.

Let me elaborate a little. I was trying to make my last post a little less confusing, by rounding. But since you have such extensive knowledge of how it all works, I will go into detail. Because I'd really appreciate your feedback. I am obsessing over this and driving myself crazy with worry, because I don't want to go back to feeling how terrible I did.

I started out on 18.5mcg of T3 (had been on about a month and a half before beginning t4). At first the t3 was good, but then I started feeling bad. I didn't want to raise it, because 25mcg had proven to be too high of a dose causing hyper symptoms. The problem with the 18.5 dose is after a while, my body needed some ft4 to convert to ft3 when med was used up and I didn't have much to give, so my ft4 went down even lower than it was before I went on the t3. Ft4 was 1.0 (.8-1.8) prior to going on ft3. Once I was on ft3 for the month and a half, I started having hyp symptoms badly. I was tested and dt4 had gone down to .7. That is when we decided to add 37.5mcg t4. I was on that for a week and a half when I decided i would reduce my t3 to 9mcg-12.5mcg a day. Well, clearly being new to thyroid disease, being impatient and desperate to feel better and having to care for a 9 month old, I may not have waited long enough for the t4 to build up before dropping my t3. Within 3 days of the t3 dose decrease, I felt very fatigued and depressed. I allowed it to go on for two weeks before I decided I needed to add back some t3 in order to feel better. So I increased t3 from 9much for 5 days to 12.5mcg for a week to 15mcg a day. At this time it had been 5 weeks on t4 so I went ahead and increased my dose to 75mcg. After a week on 75mcg and 15mcg, I began to feel a lot better. I waited an additional week on this same dose, then reduced t3 to 12.5mcg. (Going slower this time. Plan to gradually reduce t3 by 2.5mcg every week, as t4 builds up. I went way to fast the first time.) It was after being on this new dose of 75mcg and 15mcg that my levels were tested. But it was too early for the new dose increase to show in bloodwork, so I assume it was showing the prior dose numbers.

I hope this is all making sense. I know I covert from earlier testing before meds. I never tried t4 alone. Doc started me on t3 to nip the depression and thyroid issues in one. I don't think this was best in retrospect, being that since adding t4 I have felt significantly better. But I need to get my free t4 up which is hard to do adding t3 with it. Why is this? And do you think my plan of dropping 2.5mcg a week is good for weaning? I just don't want to go back to feeling how I did when I reduced the t3 before the t4 had time to build up. How long does it take for free t4 to increase on Synthroid? I know the tsh takes 4-6 weeks, but the ft4 goes up sooner. Just curious how long that takes. Or will it not go up because I'm still on too high a dose of t3? I wish I'd started on t4, this process would be so much easier.

Thanks for any help you can offer me on weaning off t3 effectively while increasing t4 to alleviate any unwanted side effects of coming off the t3.

Also, the t4 I'm taking now wouldn't be going to reverse t3 would it? Wouldn't my ft4 have to be high or at least in mid range for a while before it started going to rt3?


Because your dose is quite low for you overall, rT3 isn't as much of a concern. The biggest issue you have is trying to find a stable dose and stick to it.

What I'd usually recommend is being systematic. You need to change only one thing at a time, make sure you have a very clear reason for each change (for example you've decided to give up T3 altogether and change over to T4? That is a clear reason, and you can use it to come up with a clear reason for what to do next). Don't chop and change reasons.

Then once you decide to make a change, or work towards a specific thing, make changes of approximately 25mcg of T4 (or equivalent), then stick with that for 6 weeks and have a blood test. Then using symptoms, blood tests, and your goals make a new adjustment in the same way.

The only partial exception to this is if you're fairly stable in one format of thyroid hormone, and you want to directly change over to another. In that case you can calculate a roughly equivalent dose and change over quite quickly. From T3 to T4 I think you could do it in one go, from T4 to T3 you might go in stages, as some people feel hyper when they first start T3. It sounds like you've had that experience. The remedy for that is to start with very very small doses and increase slowly.

I don't think there is much point in reducing T3 so slowly. The important thing is that if you reduce T3, you will need to increase an equivalent amount of T4. You can try doing it all at once. You may feel less good for a week or two, but this is always true with changing a dose - you can feel worse before you feel better. There is no way to speed up this process, the hormones will not act any faster. Then wait 6 weeks and have a new blood test. You will likely need several more increases, as your current medication is too low.

The only thing I'd add to this is that changing from T3 to T4 is a slightly strange thing to do. Most people feel better on T3 than they do on T4. The usual preferred thing to do is to take a mix of T4 and T3. You may feel worse once you've changed over to T4-only, as some people do not do well on it.

You don't need to worry about the freeT4 number. T4 is just the storage hormone and doesn't really matter. FreeT3 is the most important number, and you want to get that into the top third of the range.

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I'm not sure appropriate levels of T4 are necessary if you are on T3. You just need to be well medicated on one or a mixture of both.


I am trying to slowly discontinue t3, while adding t4. I was started on t3 instead of the other way around. I want to see if I can convert t4 to t3. If I can, I'd rather be on just t4, because t3 has proven to be not for me.

That is why the free t4 level is important to me. Because I need to get that level up, so I can convert it to ft3.



Silver advocado and slowdragon are spot on. 2 wks is far too soon to be tested.

Bit confused as you said your in earlier message you definitely did convert but now hope to. There is no guarantee- no one I know does v well. Whilst you're on t3 your t4 will be lower and matters less because you are having "active "thyroid meds.

I'd give it more time and change one thing or as my specialist sometimes suggests start from scratch- you need a base line where you feel ok but can improve on.

I've never heard of getting pregnant more easily just on t4. A friend of mine had a healthy boy eventually on ndt.

Have you been tested for hashimotos and b12 folate ferretin and d3?

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Yes, been tested for all of those and they are good.

If I don't do well on T4 only, then I would add the t3 back. But I want to see how I do in just t4. I know I converted pretty good before my numbers plummeted.

T4 is necessary for proper fetal neurological development. That is why I added T4 to my t3 only, plus I was not feeling well on t3 only. My ft4 had gotten very low,l while on t3 only (as I know know is common). Thus I now need to get my fT4 up if I plan to conceive.


Please do not raise so quickly, you need to give it time, like the experts say !

And do not get too obsessed with digets.

They are a nice guideline, but not the bible!

Getting to know your symptoms is halve the ticket to find your sweetspot.

Doctors will not be able to tell you that.

You can.

My personal thyroid thermometer are my feet. Others may have a different one.

It is helpful to keep a diary, on when you changed your dosis, and to note on which days you felt good , or other symptoms. Like, for example, cold feet, dry skin, feeling happy! ,brainfog ,feeling hyper (I can feel my heart pounding ). Then look back on it from time to time.

I find it helpful to have a perscription for a bloodtest ready for when I think I need it.

All the best for you. I´m sure everything will go well, once you listen to your symptoms, and grow confident about it.


Yes I agree t4 is necessary and your tsh should be low too( btf-thyroid. Org)

You must do what you feel is right just don’t rush- I wish you good luck and keep us posted.


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