Does T4 in NDT do anything at all?: Does T4 in... - Thyroid UK

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Does T4 in NDT do anything at all?


Does T4 in NDT gets converted to T3 at all?

Or do people on NDT live only off the T3 coming from NDT/and not from T4/T3 conversion?

32 Replies

Someone a week or two vack put a link to a US site that stated T4 itself had a role. Sorry cannot provide the link.

With a bit of luck, it gest converted to T3. Otherwise, people would have to take an awful lot. If you don't convert well, it's likely you won't do well on NDT.

So I am bound to never get well since I cannot tolerate more than 15 mcg T3...

Is there a person on T4 (and even T4 + T3) who manages to convert well? I don't think so. It is the pituitary feedback loop that can never be preserved as in a healthy person once one is on hormone replacement therapy. And all this will lead to impaired conversion even in a person with the most successful conversion per se.

I don't think the feedback loop has anything to do with conversion. Plenty of people on T4 convert well. I'm sorry, I really don't understand your reasoning, there. There's no reason why you shouldn't get well. Do you know how well you convert?

If you cannot increase T3 above 15 mcg, you probably have nutritional deficiencies. Have you had your vit D, vit B12, folate and ferritin tested?

Yes, I have. Ferritin is low, I cannot raise it since my iron is good, transferrin saturation and everything else is good. I know I should have an optimal ferritin level but I cannot raise it. So I am bound to never tolerate T3...

D, B12, folate are good.

About the feedback loop:

When a person starts taking T4 alone, TSH falls down and this slows down conversion since TSH is a powerful tool in converting T4 to T3. The more FT4 goes up, the less it gets converted to FT3 because the more TSH falls down.

When one is on synthetic T4 only, TSH should not get suppressed or fall down below lower range because it hampers conversion this way and that is the feedback loop actually.

See Dr Lowe and Paul Robinson's speculations on this.

I managed to be perfectly fine (euthyroid) on only 37.5 - 42 mcg T4 for a whole nine-month period by keeping my TSH at 1.60-1.90 and thus converting T4 to T3 like crazy. The lower my TSH would get, the more hypothyroid I would become, the balance would get disrupted. Тhen I would stop T4 for a week, let my TSH go up a bit and restart taking T4.

Taking T4 only almost always interferes with the feedback loop, even in people with no conversion problems - unless you are lucky to stay on such a synthetic T4 dose that can replicate a thyroid production of a healthy person which is almost next to impossible. I had been successful in doing it but only for 9 months.

Same thing would happen if a person adds a small amount of T3 to their T4 (an amount of T3 that is not enough to compensate and fully replace one's thyroid hormone production and shut their thyroid down). By adding a small amount of T3 to T4 a person is likely to feel even more hypothyroid, since that amount of T3 no matter how tiny it is has a suppressive effect on TSH, it down-regulates one's thyroid output, and a person may end up with lower FT4 (that is normal when adding T3) but also even a lower FT3 level despite the newly added T3.

And the FT3 level will stay low/not adequate till the taken T3 dose is not raised high/adequate enough for the specific person's needs to shut his/her thyroid down.

No, the feedback loop refers to the signalling to the pituitary to say that there's not enough thyroid hormone in the blood; the pituitary producing TSH to stimulate the thyroid to make more hormone; the thyroid making more hormone; the signalling to the pituitary that there is now enough hormone in the blood; the pituitary reducing production of TSH. And, the bit that's missing there is the response of the gland. Not because you're taking T4, but because it is sick and cannot respond. Conversion doesn't rely solely on the TSH. A lot of people on T4 only, with low levels of TSH, manage to convert very well. Otherwise, the whole system would come crashing down, and even doctors would have to admit there was a problem.

It's just we odd balls on here that can't convert very well. Millions of people do very well on thyroid hormone replacement - aka levo. But, if you found your ideal dose, with an ideal TSH for you, and ideal conversion, why didn't you stick to it?

Just because your iron is good, does not mean you cannot increase your ferritin. Ferritin is the protein that stores iron. It's like an iron bank. The body puts iron in and takes it out again, as needed. But, if your bank account is low, there will come a time when there are not enough funds to take out as much as you need. That's why it's the ferritin level that is important, and should be keep optimal. Have you tried taking iron with vit C?

But, if you found your ideal dose, with an ideal TSH for you, and ideal conversion, why didn't you stick to it?

That was during pregnancy, I gave birth, my thyroid production naturally sped up and everything came upside down, I am not able to do well on 37.5-42 T4 anymore. I have tried it, to no avail...

Please, greygoose, do tell me, is it really so, can I raise ferritin even though my iron is good? Doctors tell me I cannot take iron and my ferritin is fine although low normal...

It was after having a baby that I had it measured.

Do you think pregnancy and birth can lower ferritin levels?

Doctors know nothing about it! They don't 'do' it in med school. They know nothing about thyroid/hormones, and nothing about nutrition. There is no reason you can't take iron, as long as your ferritin doesn't go over-range.

Sorry, I didn't know your perfect dose was when you were pregnant. That changes everything.

My iron fell down to borderline low while pregnant but still I felt really good on such a tiny dose of T4.

Indeed, doctors hardly know anything. And they don't bother to learn and upgrade. This is because it does not affect and concern them personally.

Do you know that 95% people, here, in Bulgaria are on T4 only. There is no alternative unless you start playing it "resourceful" and find a way out.

Yesterday I spoke to some women on a Bulgarian forum. All of them think that you cannot get better once you become hypothyroid, it is for life - your hormones will always be on the "hypo" side and you will remain symptomatic for life. I think that is because they take T4 only. Some of them have FT3s even below range and they stay like this, just putting up.

They think it is highly unlikely that I will get better.

They were trying to find answers and get better in the past but failed and they live hypothyroid.

I am grateful to God I can use English, otherwise I would not have learned all these things I know now...

It is sad. :(

In my day, pregnant women were stuffed with iron whether they needed it or not! In fact, they never even tested to find out if you needed it, just gave it too you! Total ignorance all round!

Same here. In present day. lol.

What if a woman has a b12 deficiency, what if a woman has thalassemia...

Too bad for her, because she won't get any help out of her bog standard GP!

The way in which NDT works is that the T3 in it is used directly, and if more is needed some of the T4 is converted by the body to make up any shortfall. The aim is always to get the combination of direct T3 supply and T4 conversion to give together your correct FT3 level. That the ratio of T4 to T3 in NDT is different from blood is a total red herring - this nonsense is always peddled about as a bogus criticism of NDT's hormone content. The fact is as above - get the FT3 right from the combination of direct supply and conversion, for your particular unique circumstances. Also NDT might have a property of more steadily releasing T3 and T4 to be absorbed. This is because a lot will be temporarily bound to proteins in the NDT (like thyroglobulin) and it will take a little while for the stomach acid to digest the protein and release the hormones for uptake. Taking "naked" T4 or T3 means that this is taken up straightaway and for T3 you might get more "spiking" of results

in reply to diogenes

I am so glad you said that about the ratio in NDT! I've been saying that for a very long time, but people will insist that the ratio is so important! Now I can quote you! :)

"Also NDT might have a property of more steadily releasing T3 and T4 to be absorbed."

Now that is one thing I am hoping for if I switch to NDT, especially with the T3. I am hoping for a "smoother ride" with T3 in NDT.

Thank you!

in reply to diogenes

Sorry, Diogenes, just for clarification: when you refer to the ratio of T4 to T3 in NDT, do you mean it's not important that NDT allegedly contains those hormones in different ratios compared to humans (it's often said that pigs produce more T3 and less T4 than humans do, hence the need for additional T4 in some patients)?

in reply to Hidden

Exactly; it does not matter because the body will use the T3 offered and make up with any T4 conversion required. The amount of T4 in NDT is still enough to provide for conversion as required. Think about just giving T4 only - that's as far away from the thyroid's production naturally of T3 and T4 as is possible. Much worse than NDT.

in reply to diogenes

Yes, I see what you mean and I agree with you. I spent ten years on T4 drugs only and felt absolutely miserable. NDT is much better, even though it's a shame there have been so many problems with reputable brand names such as Armour, Naturethroid and even Erfa in recent years. That reduces the number of viable options, IMHO, and that is the last thing we need.

Thank you, Diogenes! I will copy and paste that.

This is a useful video I found - might be worth a watch.

Thank you!

Justliloldme, the video won't play.

Sorry Yuliana, I've reposted below

in reply to Justliloldme

Opsi: "This video page cannot be displayed"

in reply to Bettan

I've reposted below - sorry

in reply to Justliloldme

Get a 403 Forbidden on the link you have posted.

Did you sign in somehow in order to view that?

I've reposted below - sorry

Does T4 in NDT gets converted to T3 at all? - Of course it does, usually, but sometimes it may not; all depends on circumstances. If it was not needed at all then God/Nature would not have put it there.

The ratio of T3/T4 in the natural product is makes the the medical fraternity to give (??????) patients only the same proportions of synthetic T3/T4 as is created by any normal human thyroid. Why this procedure is followed at all does not make any sense, as the 2 sets of products are very different in nature and act in completely different ways. Docs should take full notice of how the patient feels on different doses of the synthetic product, not blindly obey the recommendations of those who appear to ignore the truth and report untruths and lies to each other.

Thank you, Panda!

To watch the video you have to go to "the office of dr brad shook" Facebook page or the twitter account. His Web site has crashed. Lots of really good videos on Facebook.

Really sorry guys - hopefully this link will work x

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