Do we lose the ability to convert T4 to T3 if we supplement with T3?
This is what somone has just said to me. I've never heard this and would be grateful for an affirmation either way. I mean, that could be a tad tricky if T3 users had to revert to T4 monotherapy....cos it'd be no use to them?
That's a very good question. And one I've never seen asked before. And I don't know the answer, but somehow I doubt it - unless you count the fact that taking T3 would suppress the TSH, and you do need the TSH for some conversion, and once the body has got used to having a suppressed TSH, it might not rise again if you stopped the T3 and just took T4.
However, given that most people start taking T3 because they can't convert well anyway, I think this might be one of these myths like the one that says once you start thyroid hormone replacement you can never stop it. The truth there is that you can stop it, and your thyroid will just go back to doing what it did before. But, given that you started taking it because you were hypo, you will still be hypo.
Anyone got anything more knowledgeable to say? helvella? diogenes? jimh111?
Well, that's a great start...with additional info. Shall I say, I was challenged when bemoaning the lack of investigation and training in mainstream practice of additional T3 replacement. I can start with you answer x
Glad you like it.
From my experience of using T3 only, i had no issues going back to using T4.
That has been my experience so far. My conversion rose to the same as previously. But back on it again, as a combo, because
the amount I do convert on T4 alone correlates with feeling ugh
Why did you/would you revert to T4?
I take t4 only and works very well for me.
I had to self treat over 10 yrs ago and I made many mistakes trying everything but my mistake was to increase thyroid meds to fast and so I ended up on big doses of everything.
So I moved between protocols but at a high level. All the time the issue was the high amount of hormone I was on.
Eg 150 t4 and 50 t3
200 t4 only
60-90 t3 only
5-6 grains nth
These were periods I went through and I was not on all this at one time.
I now take 100/125 alternate days t4 only and am well.
It's Great you Sorted it out for yourself . Constancy and hard work pays off .
For myself, I was doing fine self dosing on combination therapy but my GP does not like the use of T3. During a consult that had nothing to do with thyroid he picked up that I wasn't being prescribed levo by him and persuaded me to try it his way. I felt fine for a while but then started to backslide into hypothyroid symptoms despite my tests showing slightly under range TSH. My serum T4 and T3 were in range but the T3 was only half way or just under. After several years of monitoring myself, I have always found T3 in the top quarter of the ref range and suppressed TSH correlates with less symptoms.
And imagine trying to explain to a GP that one's TSH isn't rising because of T3 supplementation!
I think I might be having that conversation this Friday! I went to see if I had a UTI, ended up seeing the GP, she said no, probably a virus. Ignored everything else I said. Asked about the creamy deposits round my eyes and said she didn’t like how low my TSH is.
I see a private endo and am on 75 of T4 and 10 of T3. I told her I was concerned about my vitD level dropping again. “It’s in range, I can’t prescribe” was her answer. Then said I had to have my TSH checked again, plus T3. 🤦🏻♀️ So I did. And it was the same as in July.
TSH 0.07 (.55-4.78) T3 5.2 (3.5-6.5)
That’s all she tested, then I was told to have a non urgent phone call with her, which is this Friday (3 weeks after blood test).
I assume she will say my TSH is too low. (She specialises in heart conditions). I won’t lower my dose. I’ll tell her I am under the impression that taking T3 naturally lowers the TSH and for her to speak to the endo as he’s ok with it.
I will do a full blood check privately in a few weeks and will post on here if anything looks awry.
I will also post on here about the phone conversation if I get major issues with the GP.
Hi just wondering what symptoms you had of low T3 as I’m on the same level of t4 as yourself my T3 level is 4.1 never any higher, thank you
I was on 100mcg of levo. Reduced to 75 when 10mcg of T3 added.
My Endo goes more by how I feel. I was running out of energy and taking 1-4 days to recover if I had a busy day. The fatigue was less severe and also my migraines and joint pain reduce when my T3 is higher. Plus I sleep better too.
I think 4.1 is pretty low on the T3 level (depending on the range of course). Do you take T4 and T3?
If on T4 only and your TSH is over 1 you might need an increase of 25mcg. If on both you might need more T3. If you put your results with ranges on a post then the wiser ladies and gents on here will give you great advice. I think results of TSH, FT4, FT3 are all important when trying to sort levels.
Hope that helps? 🙂
Thank you for your reply, I’m on T4 only, last test by medichecks was TSH 0.98 FT4 18.8 FT3 4.03 range(3.10-6.80) just got the papers out from June, I’ve had sleep issues the last 4 years, but my main issue lately is gastritis maybe low acid, I’m gf & df,
I know what you mean about recovery I used work a 6 hr shift then the next day I needed to recover this went on for years, I no longer work, but have B12 injections which really help, my endo did prescribe T3 but my dr would not and scared me a bit about heart problems, but I do have some from aboard which my daughter brought back for me so was tempted to try it..but was not sure if I should reduce my 75 of T4 ? to or stay on current dose, I used to be on 100mcg but since going gluten free it dropped and has stayed pretty much level now, all my other symptoms went away with B12 and gluten free.
I can’t comment on what to take. (Be worth your own new question for others to advise). But I have a feeling my GP tomorrow will talk about heart issues with low TSH. I have no underlying heart conditions, none in the family. I understand that T3 will naturally lower the TSH. I have no overmedicated symptoms (in fact still a few under symptoms). My T3 is not at the top or over range. I think they have been given guidelines which might be either wrong or not up to date. So, if she says anything interesting I’ll let you know. 🙂
Hi there, may I ask what symptoms you felt before you went on b12 and gluten free.
Hi Josie I had a lot of neurological symptoms, pin & needles numbness in toes, legs hands, brain fog, balance problems, slurring speech memory problems, most of what is on the list, but apparently it can be part of the gluten that does this to the gut, damaging it so you become low in nutrients, after some investigations in my medical files, turns out I had a test for coeliac which came back high positive in 1995, but I never got the biopsy done, so they did not diagnose it, so with all the b12 I’ve had and gluten free, my fatigue is a thing of the past, most of the symptoms have now gone, but I do have to use supplements to keep my levels good.
Just wondering how you got on?
Hello helbel, she just said that I could be looking at long term health issues with my TSH being so low. I told her I felt very good at present. But she has decided to write to my endo and ask him about it. So I’m still waiting. I did however, email his secretary and ask to be copied in to any reply that he sends the GP. I don’t trust her to tell me the whole truth. 🤨
Let's hope she's basing her statement on standard information. I think I'll pop up a post on low TSH.
My TSH has been low for a few years. I had a dexa scan recently with normal result. My heart flip flops when I'm hypo. I'm not taking anything for granted, though. I am self dosing and don't know which is scarier..self dosing or not being able to function within the standard TSH range. I am concerned about the information coming out about suppressed TSH. Good luck with the endo. I saw one privately and he was more concerned clinical symptoms.
He is a private endo, supposed to be quite high up (on thyroid uk list). I’m getting a bit confused by it all. A post on low TSH would be very helpful. I feel a lot better than when in T4 only and can cope with a lot more in my daily routine. My energy levels are more constant (not needing to be prepared for 1 - 4 days of rest before I could do anything again). I’m also scared that things will get worse in the future if my levels are not correct, but I suppose I should just be happy that I’m a lot better at present. Thank you for your replies. 🙂
I think we are in the same ball park. I have decided that if I feel well, my body is well...and if I don't my body is sick and prone to more disease. Not that replacement is ever as perfect as a normal thyroid gland.
Very true, but as ours aren’t normal we don’t have a choice.
Hi helbel, just got a copy of the letter from the endo to the GP. (Don’t know what hers said).
Anyway, he thanked her for her helpful letter (I’m wondering if she was pointing out stuff he already knew?).
“It May take some time to de-suppress her (my) TSH. It is not undetectable so that epidemiologically speaking she is not at increased risk. I would carry on with the current doses and repeat tests in 6 weeks”.
So, I’m none the wiser. But I feel the endo is sort of saying “go away” to the doc and leave this to me. ???
I feel fine. If anything, I could occasionally do with a little more T3. But I’ll not change it. As the colder weather sets in I’m sure I’ll be using more energy. And maybe my TSH will rise a little to please the GP.
I agree. Only if you take a lot of T3 and it down-regulates your axis this would affect conversion and thyroid secretion. The same would apply if you took a lot of T4.
Just so I've got that right, you mean continual use of T4 will down regulate T4 to T3 conversion?
Or permanently impair, which the original questioner implied.
Bearing in mind that our thyroids don't secrete.
Ive reread your answer, thanks....that T3 supplementation could impair conversion. And using T4 and or T3 inhibits secretion. That then implies use of T3 is a last resort because we are playing ducks and drakes with the bodies ability to convert synthetic T4. Sort of talking to myself here.
Gosh..further - that T3/T4 combined replacement would still end in loss of conversion - having to raise the T3 ratio as conversion declines to eventual T3 monotherapy. Feel free to tell me I'm talking rubbish... .got the wind up now.
Well, no, that's not exactly what Jim said. And using T4 and T3 can inhibit secretion temporarily. If you stopped taking them your thyroid would start secreting as much as it was able again. It's only when you down-regulate your axis that your TSH fails to rise again.
I certainly wouldn't say it was a last resort to take T3 because often you don't have the choice. I wouldn't exactly say you were talking rubbish, but I don't think you've quite understood what was said.
If the body loses the ability to convert synthetic T4 to T3 because it has been impaired by supplementing with T3, then T4 replacement is of no use because the body cannot convert it into the active T3. As opposed to down regulation of hormone production, or the need to convert because T4 or T3 is being artificially replaced. It's the permanent impairment that is of concern. I'm still trying to find some scientific information too.
If you take a lot of hormone for a considerable time such that your TSH is virtually zero it will down-regulate your axis. In this case your thyroid will be under stimulated. Since TSH stimulates conversion in some tissues your rate of conversion will also be reduced. Sometimes the axis recovers, sometimes it doesn't.
If you don't take high doses of hormone and your TSH doesn't go low you will be fine, no long term effects.
Hi Jim, what does ‘down regulate the axis’ mean? Is it just another way of saying suppressed TSH?
No. If you have high thyroid hormone levels that suppress your TSH for a long time (many months?) your 'set point' can be down-regulated'. This means your TSH for given fT3, fT4 levels ends up lower than it used to be. This results in less stimulation of your thyroid to secrete hormone and since TSH can promote T4 to T3 conversion you also get less conversion. So you don't want your axis down-regulated (if you have a choice!).
Thank you for that, I’ve never heard of that before. However it is probably what’s happened to me for many many years now. But good to have an explanation.
Would that still show the in the serum free TS as the usual higher T4 and lower T3, or in difficulty raising T3 from replacement. Does taking T3 override that issue once the damage is done?
Does the possibility of "down regulating your axis" apply to those who have had a complete thyroidectomy?
Yes. More so if they had a period of thyrotoxicosis. The axis can be down-regulated if thyroid hormone levels are high for many months.
Wow. I had my thyroid removed 10 years ago and never heard of this! I've been on levo only except for this summer. I experimented with an OTC dessicated thyroid for a month which put my TSH over 100. I got back on levo-only for a couple months and just last month was able to get some T3. Currently taking 50mcg levo, 12.5mcg liothyrodine sodium. Haven't had my blood work done yet to see how my body is responding. Hope I didn't mess myself up!
Thank you for the reply and info.
If you take a lot of hormone for a considerable time such that your TSH is virtually zero it will down-regulate your axis. Does that then also apply to those that had Thyroidectomy ?
Yes. It is the suppression of the TSH that affects the pituitary, doesn't matter where the hormone comes from.
Not only is this correct, but I was shocked to discover, in the middle of a medical journal article that "high serum t4 impairs systemic t3 production" and that this has been know for some decades.
This means there is some culpability on the part of medical professionals who routinely increase t4 doses, despite repeated test results demonstrating zero movement in Free t3. In fact, paradoxically, it seems the higher the dose of thyroxine, the more t3-deficient symptoms emerge and what is often needed is a decrease in t4 dose for symptom relief.
Even more need to measure serum T3 from the outset, gosh.
There is always a great need to test FT3, but it is not recognised by the NHS because doctors do not learn about T3 in med school. It all comes down to their terrible education. The knowledge is there, it can be found on internet, but they would need to look for it, and they're just not interested.
Yes, when the FT4 level gets to a certain high point, it starts converting to more rT3 than T3. This is a natural reaction to stop you going hyper. This knowledge may have been around for a long, long time, but I doubt you'll find many - if any - endos and GPs that know about it, because they just don't do it in med school.
I've had a chat with the person who made the original statement. They are hunting down a paper they think they read it in. I'm interested to know if the paper specifically says permanent impairment as they imply.
That would be interesting, yes.
"when the FT4 level gets to a certain high point, it starts converting to more rT3 than T3."
So how do you know when you've reached that point? When you feel worse instead of better when T4 is increased or by measuring the RT3? Or what?
You possibly would feel worse, yes. But, when you have FT4 and FT3 tested, you will see that your FT4 has got higher, but your FT3 has stayed the same - or may even have decreased. If you tested the rT3, it would be high, but you don't need to test it to see what's happening. The FT4/3 will tell you.
I'm still only up to 50mcg Levo. Is there a point where I should ask to have t3 and T4 tested (and be prepared to fight for it if necessary)? Last time they only tested TSH, which was still high on 25mcg. The note on the results said “Increased TSH suggestive of poor compliance/inadequate dose".
"Poor compliance"! Suppose they thought maybe I wasn't taking the tablets!!!
Oh dear! They are so ignorant! Always blame the patient if at all possible! That's their motto. If your TSH was higher it was because your dose of levo was too low - 25 mcg is high enough to stop your thyroid's production, but not enough to replace it, so of course the TSH rises, you've had a reduction in your total. And they don't know that? Incredible.
It's when your TSH gets down to about one that you need to start nagging about testing the Frees. Until then, you know they're going to be low. But, at that point, the TSH is less reliable and you need to see the Frees - both to know how much you have and to see how well you convert. But, doctors don't know that, either!
"It's when your TSH gets down to about one that you need to start nagging about testing the Frees..."
Thank you, GG, didn't know that. So they are doing OK so far and I don't have to nag just yet! Good.
Though I think it will be a while before the TSH gets below 1, lol
March FT4 13.5 pmol/L (11.0-25.0) Before taking any Levo
TSH 5.94 mU/L (0.27-4.20)
May FT4 12.9 (on 25mcg Levo)
July FT4 not tested (on 50mcg Levo)
Another blood test tomorrow, hopefully followed by an increase!
That's a slow raise by your GP. Did he explain why?
I read on here that it was 25mcg at first because I am over 50 and have high blood pressure.
Ah. I understand about the BP worry. I believe it's slow due to age and or health in general. I was also told that we are considered elderly patients after 52.... great
I'm WELL over 50, so fair enough!
And in the wrong side of sixty. Sigh
I just hit “elderly” then as I was 53 last week 😆
Yes, I hope so too! Bad enough starting you on 25! Honestly! 50 is not old! My life started at 50, when I walked out on my ex! lol
I've just turned 70, so suppose 25 is the cautious way to start!
I suppose so, but is it over-cautious? I was 55 when I was diagnosed, and I was started on 50 mcg. Of course, that was 18 years ago and in France, but it didn't do me any harm.
Maybe they just like to see us coming back for more
Oh, of course they do! They're thrilled and delighted to see us! lol
Haaa love it 🤗😘
Sorry, a little late to this thread but v interesting!
So greygoose , if this were the case and you still felt hypo symptoms, would opting to trial T3 then address this issue (ideally)?
I ask as I fear this might be exactly what my bloods will look like when I next test them... could be wrong, fingers crossed!
I'm sorry, I don't know to which comment you are replying. If what is the case?
I’m sorry! For some reason my reply decided to jump in several lines down!
I was replying to your comment that begins ‘you would possibly feel worse...” re FT3/FT4
Sorry about that!
Yes, it does that. And, when people are replying in vast numbers, it can get very confusing! lol
OK, so you are afraid you're going to find you have a conversion problem because you still have symptoms. Well, often happens. In which case, the only way to feel better would be to add T3 to a reduced dose of levo. There are so many reasons that conversion can be poor, that's it's often not possible to find the reason and correct it. Of course, nutrients do need to be optimal, to give you the best possible chance. But, it's not always down to that. A lot of Hashi's people are poor converters simple because they have Hashi's, and there's nothing they can do about that.
So, you would need to ask for a trial of T3. But, whether your endo would understand what's going on is somewhat doubtful. A lot of them 'don't believe' in poor conversion - although how they get away with not believing in something that's just in front of their eyes, I don't know. And a lot more 'don't believe' in T3! As incredible as that might sound. So, I don't know what your chances are of getting a trial.
But, post your results here, when you get them, and we'll be able to tell you how well you're converting.
There is another aspect to this. If you give so much T4 as to suppress TSH, then if you have any thyroid left working, this suppresses the production of T3 direct by the thyroid remnant. The body conversion often can't make up for this and can also be down regulated so there is a double problem. Body conversion problems stand alone with no working thyroid at all. Longterm pituitary suppression is often difficult to reverse.
This is so important to know.
Exactly. Oh why don't we all try to educate the medics who treat us. Our combined knowledge could change the face of thyroid treatment.
When I was finally clear of my cancer, I was put on 200 mcg of Levothyroxine by the Oncologist. Results came out at FT3 6.8 (top of range) and FT4 42 (top of range is 22). I felt like death for 2 years and the only answer she could give was "Spot on. Well done. A nicely suppressed TSH and FT3 just where we want it.". When I queried the very high FT4, the doc said "We don't worry about that. The high FT4 is because of your high dose of Levo. We're only bothered about TSH and FT3".
Two years later I went for a second opinion. it took the efforts of a thyroid oncologist and and endocrinologist to get the FT4 down and sort me out. They told me that the FT3 was probably lower than 6.8 because of distortion.
I can forgive GPs for their lack of knowledge - but the doctor who medicated and monitored me was a supposed expert. Frightening.
What your saying makes a lot of sense to me . After my TT I was dosed on high doses of T-4 for suppression purposes . I can Not get my FT-3 higher than 2.9 at the most . And reference range being 2.3-4.2 pg/mL and TSH being 0/07 with reference range being o.40-4.50 mIU/L . Lowering my T4 helped with my raising my FT-3 and helped my TSH rise a bit too . Lowering just by 25mcg T-4 .
" Lowering my T4 helped with my raising my FT-3 and helped my TSH rise a bit too . Lowering just by 25mcg T-4 ."
That this is not the topic of a new thread and the topic of every discussion regarding thyroid hormone replacement is beyond unfortunate.
I've been reading this forum for two years and the monolithic "Symptoms? Raise your t4 dose" approach has so consistently failed to produce the expected results that I cannot believe more people have not considered reducing their doses.
I have. And I can say, unequivocally, that almost instantaneously, I experienced improvement. The most fascinating thing, to me, is that when I lowered my t4, I required less t3 as well! My perception is that while over-replaced on t4, not only was my t4 to t3 conversion inhibited, but it's as if my absorption or my cell receptivity was impaired as well. This paradox of "less is more" is one I'm super, super excited about.
Thank you for taking the time to respond, jgelliss!
I started taking NDT again, two weeks ago, in combination with T3, after 3 months solely on T3. Without blood tests results,, I go with how I feel, & presently that I'm converting it so well, I've reduced my T3 further for the past few days.
I've never taken T4, so I don't know whether that would have the same effect, or if it's the other hormones in NDT that agree with me. I did mess up swapping T3 without a gradual reduction, to NDT alone a few years ago,, & made myself very poorly indeed. It felt as though I'd no natural thyroid hormone production whatsoever, & it took months to feel better. I felt more hypo than before I started taking any thyroid hormones, so assume I've stopped producing them, but do convert the T4 in NDT to T3 effectively agter taking T3.
I too go by how I feel but also take regular tests to watch trends, keep an eye on my ft3. My ft3 went above range once and I felt very hypothyroid.
I'm still waiting for my latest blood test results as the hospital didn't process them in time for my appointment. I don't think I've ever taken enough T3 to be hyper, as I notice excess hunger as a sign to reduce, & dry lips/itchy shins to tell me to add NDT.
My experience is that t3 has helped me convert better! Possibly by lowering rt3 (Just a guess).
Before adding t3 my FT3 wasn’t high enough, my ft4 constantly over range. With the addition of t3 my FT3 is good now and my ft4 has lowered which means my body is using it.
I tried lowering just my t4 after that and my FT3 also lowered. So I raised my dose back now and for me the t4 is just as important as the t3 I take.
So from my little experiment I’d say it helped me convert better
Sometimes the only way to know is to be your own guinea pig
No, actually, it doesn't mean that your body is using it. When you take T3 the FT4 level decreases, even if you're still taking the same dose of levo. There was a big discussion on here a while ago about why. Seems nobody knows what, but it seems that it doesn't mean your body is using it, more likely excreting excess.
I remember that. But what does it mean if I reduce t4 and FT3 also lowers and so does ft4? Does that not mean I’m converting? Before taking t3 when they lowered my t4, my tsh would rise, but ft4 would also rise and FT3 unaffected, so I think before I wasn’t converting nearly as well.
Isn’t it possible that the t3 has lowered my rt3 then making conversion easier?
There are degrees of converting. If you couldn't convert at all, you would have died on T4 only if your thyroid wasn't working. You will convert some of the T4 you're taking, even when taking T3. But, the fact that your FT4 reduced when you adding T3 doesn't mean that adding the T3 improved your conversion - I really don't see how it could.
Taking T3 doesn't lower rT3. Reducing T4 reduces rT3. And rT3 does not affect conversion. It is the result of poor conversion.
Here is an article here talking about t4-t3 combo therapy to reduce rt3 with the aims of helping conversion. That’s what I’m on a combo therapy.
Forget the fact that my ft4 reduced after starting t3, I know that would happen regardless.
What I’m thinking about is the fact that I couldn’t convert before, docs kept reducing my levo because my ft4 kept going up, even when reducing my ft4 went higher! And yes I felt like absolute shit, I felt better before taking levo. I was convinced that I would need t3 only or NDT.
Anyway all my GPs were scratching their heads so I finally got referral to an endo. After going through 3 endo who said I’m fine with a tsh of 4 and ft4 well over range (FT3 less than half) I finally found an endo who gave me a small dose of t3. Then on the next test he raised my t3 and t4 together. I didn’t complain about the t4 cuz I was also getting more t3.
On a recent visit we decided to try reducing the levo from 100 to 88mcg while leaving the t3 alone to see if I would do well with less levo. Actually I did worse and my FT3 dropped to halfway in the range. So rather than asking for more t3 I decided to raise my t4 and I feel good on this ratio of 100/10.
So surely I’m converting better now am I not? I know I don’t have any technical info but my experiences and last couple years of results show that t4 is doing something now when before it did nothing.
I should mention that I also take zinc to help with conversion so that could have an effect also
It's not possible that the levo was doing nothing before or, as I said, you would be dead. Some of it was being converted - obviously some of it still is - or your FT3 wouldn't have been mid-range. But, if your conversion has improved, it would be more down to the zinc than the T3.
As for the article, he doesn't make it very clear. But the key phrase is this :
By providing the body with some or all of the T3 that it needs, the thyroid will produce less T4. With less T4 to convert to RT3, the patient’s system can slowly regain proper thyroid hormone balance.
'With less T4 to convert to rT3...' Of course, he is assuming that your thyroid is still capable of producing T4, that you haven't had a TT, or had your thyroid killed by Hashi's, and that your thyroid hasn't just stopped producing all hormone due to the fact that you're taking thyroid hormone replacement in the first place. But, that aside, if you reduce your T4 by any means, you will have less rT3. Stop the T4 completely, be on T3 only, and you will have no rT3 at all. The point is taking too much T4. When the FT4 level gets to a certain point in the range, it will start converting to more rT3 than FT3. Nowhere in that article does he say that it's the exogenous T3 lowering the rT3. He says, in a round-about way that lowering T4 lowers rT3. Nowhere does he say that it's the rT3 making you ill, but he does hint at the fact that you're ill because you now have less FT3. It's low T3 that makes you hypo and causes symptoms. He does blather on a little bit about endos who believe that rT3 is 'just' an inactive metabolite and they're wrong, etc. But, nowhere does he explain what exactly the rT3 does. Well, as far as we know, it doesn't do anything - it is an inactive metabolite. It's the fact that T4 is converting into rT3 rather than FT3 that causes the problem, because you are left with lower levels of T3.
This is always a problem in medicine, I find, the difficulty doctors have with distinguishing between cause and effect. They are always inclined to put the cart before the horse - the cart being the high rT3, and the horse being low levels of FT3.
Don’t forget that as docs tried to lower my t4 my FT3 remained unchanged and ft4 went up.
Also as you said I’d be dead “if” (and that’s a big if) my thyroid wasn’t functioning. Well my thyroid was still functioning, and I can show test results before and after starting levo my FT3 always stayed around halfway in range regardless of the t4, I attribute that number to my thyroid an not the levo. My tsh was also high on diagnosis so my ft4 was actually not low either way, it was around the top quarter, in fact if you looked at just my ft4 and FT3 without meds you’d think meh not so bad, but tsh was 20+ and rising.
We’re all in different boats, and our specific circumstances dictate what works for us. I don’t doubt that some amount of that t4 did something, but I can certainly tell you as my tsh went down and ft4 went up I only got worse. And then the lowering of t4 did nothing to lower my ft4. So my conversion was poor at best.
I don’t claim to know without a shadow of a doubt, but please don’t continue to discredit my experience. As you said everyone agrees that ft4 lowers when t3 is introduced but nobody really knows why. The fact is there is a lot we don’t know so keep an open mind to people’s experiences, and don’t just look at articles as 100% certainty.
There are more articles out there showing how introducing t3 can have an effect on metabolic processes that also then lead to better conversion. One example is people with leptin resistance (who surprisingly tend to have high rt3) are given t3 to lower both rt3 and reduce leptin resistance. T3 has such an effect on so many systems that it is quite possible by affecting on thing it can come back around and boost conversion. These are things we haven’t studied enough to really know for sure! But that doesn’t mean we should discount them.
Here’s a quick short article about the leptin resistance for example and how t3 works to rebalance conversion, if you are interested to read more on this subject I can find you some better resources: wilsonssyndrome.com/leptin-...
And about the zinc, I’ve been taking that since the start, while I was on levo alone, so what effect it has is probably not the entire story, as it didn’t do anything for me for the first year+, I’ve always taken the same amount and same brand. I wanted to mention it out of transparency.
I'm not discrediting your experience, not at all. I'm just questioning your interpretation of it. If you state that taking T3 improves conversion, you need to have something more than that to back it up.
But, I'm not going to discuss it anymore. Just be careful what and where you read, because there's a lot of rubbish written about thyroid.
I think I read that on tired thyroid's blog? That some exogenous T3 aids in conversion, but I'm afraid I don't recall any details.
Hm… It does seem rather doubtful to me.
Looks like it might be in critical illness, but I'm afraid I've run out time for the next few days to read it properly. But this might be what I recall:
" In fact, the presence of T3 itself helps T4 conversion to T3 during prolonged critical illness. "
Debaveye Y, Ellger B, Mebis L, Darras VM, Van den Berghe G. Regulation of tissue iodothyronine deiodinase activity in a model of prolonged critical illness. Thyroid. 2008 May;18(5):551-60. ncbi.nlm.nih.gov/pubmed/184...
Thank you for the links. Doesn't sound like that's quite the same as what happens in day to day hypothyroidism, though.
I would not take any notice of this article. Unfortunately Holtorf publishes many articles that contain errors, there seems to be insufficient care taken to verify the accuracy of what is written. Or a lack of knowledge of thyroid hormone actitity.
The role of rT3 is poorly understood, it doesn't seem to do much. It is wrong to suggest it is an 'emeregency brake'. If we have to have such an analogy it would be better to describe it as a 'neutral gear'. There are many reasons for rT3 levels increasing, the primary one being high T4 levels - taking lots of levothyroxine. Other causes generally fall under the term 'non-thyroidal illness' which used to be called 'euthyroid sick syndrome'. Depression, severe illness, starvation diets can all reduce T3 and increase rT3 levels. I don't like the suggestion that CFS/ME and fibromyalgia cause elevated rT3, it seems more likely these illnesses are (in some cases) caused by hypothyrodism.
SHBG is a marker for thyroid hormone activity in the liver, specifically T3 binding to TRB1 receptors. Unfortunately, SHBG levels vary so widely between individuals it can only be used as a very rough guide.
The 'T3/rT3' ratio is pseudo-science, you are giving the impression of mathematical accuracy in a diagnosis when there is no basis for such an assumption. It's just as bad as blind reliance on TSH. The ratio is comparing apples and pears, free T3 with total rT3.
I wouldn't read these articles, you end up with misleading messages and the need to 'unlearn' incorrect statements.
Oh, I do so agree with all of that!
I agree with you that a lot of articles are misleading. Personally I don’t know anything about this author but I do take a lot with a grain of salt and try to siphon through a lot of info to get an idea of something, rather than take any article at its word.
Clearly I didn’t choose the best article.
And you’re damn right also when you call it pseudo science, that’s because it’s not really studied and the info is there based on people taking other random studies and trying to find correlation. But that doesn’t mean that if we did study it we wouldn’t find a link. I’m just saying it’s possible, not probable.
If you have more info on t3/rt3, good sources, please share because I’m always looking for reputable info.
I don't know of any good succinct source of information on the role of rT3 other than it is a route for protecting against thyrotoxicity and recycling iodine. It used to be thought that rT3 blocked the action of T3 but there is no evidence it does this. In truth very little is known about rT3. It probably has a role, everything the body produces tends to have some roles, we just don't know what it does. Sorry not to be much help but the honest answer is nobody has a good understanding of rT3.
Ok well I appreciate the explanation. Thanks
There's a lot about rT3 here that should be read, simply because it contradicts Holtorf: tiredthyroid.com/rt3.html
This page talks about how T3 stimulates T4 conversion, and explains what you experienced: tiredthyroid.com/blog/2016/...
Wow thank you so much for these resources! It’s interesting to see that the old info I learned about rt3 can be wrong. But the second link really does give an explanation to my experience and seems rather likely.
I’m going to have to read the references and familiarize myself better with deiodinase, but this is a great starting point 😊
I should have added the word permanently.
Studies have shown in rats that if you take T3 over a significant period (3 weeks in rats over their 3 year average lifetime - which equates to about a year and half in ours) changes occur in the readout control of several genes. On stopping the T3, many of the changes do not revert to what they were. This is called epigenetic change. If you give T3 for only a short time, then most of the genes return to normal activity. So if this occurs in humans, there are irreversible changes in gene readout with longterm T3 therapy. This may affect conversion. It also will hinder successful return to T4 therapy.
Thank you. This was the concern. I will refer your answer if I may?
Would you provide a link to this/these study/ies please?
If you want bed time reading on a comprehensive look at control of thyroid function:
Wow.. reading it now!
Thank You So Much for this Very Valuable Information .
Are you referring to T3-only treatment? Or does this epigenetic change happen even with T4-T3 combo therapy?
How fascinating. Thank you for that! Do you happen to know the citation? Cheers.
The paper is in
Endocrinology, DOI: 10.1210/en.2015-1848
Desensitization and incomplete recovery of hepatic target genes after chronic thyroid hormone treatment and withdrawal in male adult mice.
Kenji Ohba. Melvin Khee-Shing Leow, Brijesh Kumar Singh, Rohit Anthony Sinha, Ronny Lesmana, Xiao-Hui Liao , Sujoy Ghosh , Samuel Refetoff , Judy Chia Ghee Sng , Paul Michael Yen.
Just reading it now. Leading to more questions. Ill need to read it several times 😯
I am very interested in this thread because I have taken T3 only for around 6 years now (luckily for me supplied by the NHS). I did initially take a little T3 with T4 but never felt as good on that as T3 only. However last year an Endo tried to get me to reduce the T3 gradually over 3 or 4 months and with each rise my immune system struggled (constant colds even though it was summer) and less energy and eventually more migraines too. I stopped the experiment in the end and went back to T3 only with my GP's support.
I feel in myself that things in my body have changed, but of course 6 years is a long time and there are bound to be changes as I am also ageing. When I look back to how I was on T4 only for 17 years, I certainly had problems - lowish FT3, increase in weight and diagnosis of ME/CFS so I hoped to improve those things on T3 only, but I did function fairly well within my limits. I did lose weight, though some has gone back on again, and my FT3 is no longer low, but my energy is not as good as it was when I had been on T3 only a few years back. I don't know if I made a mistake in going T3 only. I did try NDT a couple of years back and felt absolutely terrible - very hypo feeling for the 6 weeks I was on it despite slowly increasing the dose. I have not had a TT so it's hard to know why T4 no longer agrees with me, and wonder if I have in fact been down regulated via the mechanism that you describe via epigenetics.
Taking T4 for many years and then taking T3 for several will have had quite profound effects on your regulation of T4-T3 conversion and its relation to TSH. After this time, I'm quite certain you will have irreversible epigenetic changes and it will be optimal to settle on what works best and stick with it.
Thank you for your thoughts on this diogenes. I am wondering if I could use this as an argument for staying on T3 only if I should ever face that issue again with the NHS, which I fear I might at some point. Would they understand the implications I wonder?! (re the epigenetic changes).
Dusty answer I'm afraid: at this time no! They are lightyears behind modern knowledge.
Oh dear. I fear I may end up in a worse state than I started with then if I get forced down the T4 route at any point. Especially difficult now that T3 prices have shot up both here, and for anyone trying to buy it in. Fingers crossed for me then....
I think you have raised an interesting question but as someone without a thyroid the physiological mechanisms will be different. I have to rely solely on t4 conversion in the body without any primary production of t3 from the thyroid. In the research into hypothyroidism that is carried out all forms of hypothyroidism are lumped together and deemed equal, which is obviously untrue. A person with hashimoto’s disease will respond differently to someone without a thyroid, or to someone with secondary hypothyroidism. I think this discrepancy invalidates a lot of the research as it is not clear how the different populations respond. It is poor science.
And there must be shades of grey in the patient that still has a thyroid gland according to degrees of functioning. I often wonder if the end point is the same once our thyroids have finally atrophied. Aside from those that have a damaged or no thyroid gland and without autoimmune disease.
No. Many people take T3 only for quite a long time - up to 12 months or so - after a thyroidectomy until treatment and final scan complete. They then have Levothyroxine at the determined dose and usually convert normally.
Thanks very much everybody. Much to think about, and question later.
Yes, you do, if the tsh is non existant..take t3 far from t4 and maybe you could conver a bit but even then i doubt it.. take t3 3-4 times a day and t4 just for sake of having both hormones, altough you dont really need t4 at all.. i cut it out, i see no need for having it, im bald anyway tho
Generally, you'd only be on T3 if you couldn't convert T4 to T3. So yes, it's more than a tad tricky.
So is the answer is not to mess with T3 if one's conversion of synthetic T4 to T3 is in tact? Where does this leave long term combination therapy for those whose coversion is a bit stunted.....
Continuing on combined therapy for life. There's no other reasonable option.
You are So Right . It took me 23 years to realize that I was missing a very valuable component to my T-4 . Every Dr /Endo FAILED to give me any T-3 knowingly that I was a TT patient and had terrible palpitations that held me back from living a normal life . I may add to the mixture of Dr's even the Cardiologist I went to see Missed it too . Go Figure . I Learned A Big Lesson From My Thyroid Journey . To Learn as Much As Possible About Our Thyroid Illness . And To TRUST Ourselves . To Advocate ! Advocate ! Advocate ! For Oneself . Be Persistent Till One Succeeds .
I take t3 and t4. I was fortunate to have 4 years of normal tft results to know what my baseline ft3 and ft4 were prior to thyroidectomy. Post surgery I felt well for 2 months on liothyronine prior to rai, after which I was transitioned onto levothyroxine only. I felt dreadful. After 9 months struggling I looked more closely at my tft’s and noticed that my ft3 was much lower that before surgery although my ft4 was at a similar level. I did some research and opted to self treat with additional liothyronine and monitor with private blood tests. My ft3 and ft4 are now at similar levels to before surgery although TSH is suppressed ( not a problem at present as kept suppressed after cancer for 10 yrs). I presume that the lower ft3 was due to not having any produced by the thyroid and that tissue conversion couldn’t make up the deficit. The fallacy that levothyroxine only replicates normal physiology. I feel much better than on ft4 only, no longer falling asleep whilst driving, able to think more clearly and to hold down a stressful job. Sadly nhs won’t support t3 in my area although surgeon sympathetic and supportive, endo adamantly against it.
Your reply reinforces what I've been advocating for some time. That all or as many as possible healthy people should say around 20 years of age have FT4 and F3 measurements to assess their placement in the reference ranges. It could also be done say at 4 or 5 years old, kowing that children have 10-15% higher FT3 than when adult.These will give targets for future therapy if needed. Otherwise one is in the dark as to what to do when disease strikes. I've put this to doctors in the past and their total inability to understand what I was talking about and why to do it said it all as regards medical intelligence and incomprehension of the tension between the individual result and the range..
Which is precisely why I advocated that my children all get a TFT test in their 20-30s so that there is a healthy base line to compare any deviations against in the future. Hypothyroidism certainly runs in my family, my mother, her siblings and grandmother all had it and I developed it in my early 40s, although it wasn't actually diagnosed until I was 50 when my TSH finally hit the magic 10 mark... and by which time I was already on my knees!
Isn't That A SHAME ????? One needs to feel so Very Sick to be taken Seriously ??? What's Wrong With This PICTURE ????? Personally I think thyroid meds should be available over the counter . If one gets a headache there are different meds over the counter we don't need scripts for that . And for many other things too . Why not Thyroid Meds ?????? We should be able to test with over the counter strips for our thyroid values too . We have strips for everything . We could be saving lots of money that way too . Or is That The PROBLEM ???
Some super suggestions here. It would be interesting to see what thyroid meds were on offer? Still just Levothyroxine? It would be interesting to see how much uptake of this there would be and I bet there would be no available T3 or NDT. The Big Pharma companies would have the situation well in hand.
Personally I think that "BIG PHARMA " and "MEDICAL ACADAIMIA " wants a Sick Society . And Throw the Politicians into the BIG MIX TOO . It all boils down to
I think most commoner garden reasonably thinking folk would agree with you.
Sadly, there are plenty of people out there who would abuse the availability of over-the-counter T3 for all the wrong reasons (body-building and slimming to name but two), so I do think a certain amount of control has to be in place on that. However, the NHS should go shopping around to find the best deal for it... It's ludicrous to think that they are paying £258 for just 28 tablets of 20mcg Mercury/Concordia T3 that are not even contained in blister packs, when these same tablets made by Thybon Henning in Germany could be sourced at less than €30 for 30 x 20mcg! But then again, I guess Brexshit would put paid to that too... so we'd be back to square one anyway! 😡
I often wondered what mine would have said, but it didn't occur me to go to my doctor and say "Hey Doc, I feel great! Quick, do a blood test!" My guess, is that my personal set point would have been on the higher end.
Huge agreement with blanket testing at a young age.
This situation looks like an 'epidemic' waiting to explode.. Those of us here are the lucky ones but there must be many more who are suffering (dying even) with no prospect of either a correct diagnosis or treatment - far less understanding their condition - in order to achieve better health.
It is a mystery to me (all of us here) why the medical profession cannot see (or more likely are unwilling to acknowledge) what is staring them in the face. Your research included.
T3-only (self medicating, private testing and buying) has hugely improved life for me but I had to waif till I was 72 to find the solution. I have a DIO2 polymorphism. if I end up in hospital/care I shudder to think how the NHS will treat me (not!) and the consequences scare the socks of me! Must stay healthy now!
It is a scandal of seismic proportion and nothing short of neglect.....yet medics continue to bury their heads in the sand and to defend a completely useless diagnostic and treatment protocol.
Sorry, this is just another rant, I know many have said the same before ...
Thank you for the helpful info and links ....knowledge is power!
I use combination and noticed once beginning T3 meds my T4 levels gradually reduced so much, they were barely registering in the range. Once I slightly increased my T4, my FT3 became over range very quickly and so conversion didn't seem a problem. I am to all intent and purposes supplementing with T3. If what I think is true, then my conversion appears better now than whenever I took T4 meds only.
But if we supplemented with T3 only, there is no exogenous T4 to convert. Conversion, and secretion (if we have any active thyroid gland left) is bypassed. My concern is that continual use of T3 (singly or in combination) would eventually permanently inhibit conversion by the body. See Diogenes' answer further up
Further to that...what if T3 became contraindicated after prolonged use and one had to revert to T4, or, perhaps that doesn't apply because careful dose titration according to individual requirements would be the answer to avoid overstimulation?
Great thread folks!
Just outlined what has happened to me. My experience.
I know I keep rolling out the same old request. This is a great thread and lots of food for thought for good research.
I had my thyroid removed 20 years ago,was first on Thyroxine for a short while then not doing very well so put on T3 as well.I had been taking 75mcg thyroxine and 20mcg of T3 for nearly 20 years,doing o.k. My TSH has always been supressed. Then last year I was asked by my doctor to trial just thyroxine, due to the cost of T3. It seems now that my body cannot tolerate any more than 75 mcg of thyroxine,any more than that gives me palpitations and sky high blood pressure. But I have had to go back on the T3 because 75mcg thyroxine isn't enough on it's own. So maybe yes after years on T3 my body is not now converting because it is getting given the T3, or maybe because I have no thyroid it can't convert much anyway.
Did you know your free TS at the same time of levo only trial?
Yes.luckily before swapping it I saw the Endo, who did all blood tests. T4 14.2,T3 5.4 TSH 0.04. After on 100 mcg Thyroxine alone it was T4 19.6, T3 4.4, TSH 0.03. But I could not stay on the 100mcg thyroxine as it was giving me palpitations and my blood pressure was very high, I was worried I would have a stroke. So Endo saying T3 was suppressing the TSH made no difference, as on T4 alone TSH was still suppressed.
Very interesting. Just goes to show the go to panel doesn't tell everything.
I think a tiny bit is convertd by the thyroid and about 80 percent by the liver and kidneys. Would need to o check on that. Did your endo know or mention conversion issues?
#diogenes can comment on the percent converted by the thyroid, I believe it was estimated at 25%, a reference to the relevant paper would be nice for my own interest.
The liver and kidneys express type-1 deiodinase (D1). It is estimated that 70% of conversion is by type-2 deiodinase (D2) and 15% by D1 so clearly the liver and kidneys have a minor contribution. See ncbi.nlm.nih.gov/pmc/articl... .
A point to note is that these are the proportions of circulating T3. D2 also produces local T3 some of which does not get into circulation.
The reference was a fleeting indication of a small study that we could use to estimate average thyroid direct contribution to T3 in the body as opposed to T4-T3 conversion. As of this moment, we've designed a long term study to get answers to (we hope) a) what does the healthy thyroid contribute to T3 in the whole body and b) what is the variation in this contribution (the reference range for this parameter). c) does this have any connection with the FT3 level one has in health (re future problems in disease) e.g. high FT3 in health, problems later? d) does that indicate what subjects might need combo therapy in future as opposed to T4 only. This is really longterm and I can't give a timescale for its conclusion (because the suitable patients are rather few in number). As a baseline a study by Pilo et al calculated a 20% contribution on average. But they used lugol's to stop radioactive input into the healthy thyroid in their studies. This inhibits T4-T3 conversion somewhat so that their estimate must be a minimum.
Thanks for the detailed reply. I think this is the Pilo paper you're referring to citeseerx.ist.psu.edu/viewd... . It looks even more challenging that your papers! So I will have a read when I'm feeling on form.
Good luck with your proposed study, it certainly is ambitious and fundamental to changing treatment attitudes.
This is my first comment here and wanted to congratulate you for the insightful exchange.
Quick question: Does it make sense that when I feel well, I do tests for TSH, FT3 and FT4 so that I have a baseline of what values correspond to feeling well?
I was diagnosed Hashimoto 2 years ago. Went progressively from 25 mcg up to 100 mcg Thyroxine. Over the two years was feeling mostly great with episodes of fatigue and very low energy. Dosis raised after every episode. It seems like every dosis increasing brings TSH down but then after some time, TSH increases again. My ending didn’t seem bothered testing FT4 and FT3. I tested FT4 once and was at 22 although TSH was 2.4 and was feeling very tired.
If your Hashimotos, have you identified the critter that's causing the mayhem? Check for Candida EBV Lyme etc. This is why autoimmune thyroiditis can swing so much, it's trying to deal with an invader, check Zinc Copper n Iron, Iron is probably high suppressing the Zinc...
It is, isn't it. Valuable contributions from all, and rewarded with views and expertise of very knowledgeable folks.
Your testing when feeling good for a baseline measurement makes good sense to me. One of the reasons things might have changed for you is the gradual atrophy of the thyroid gland as the disease progresses and the thyroid output dwindles. It might be worth running that in a specific post so admin can pick it up and comment.
I read this whole page, all the answers and arguments, and it struck me that I could have been reading a paper wherein a group of doctors are arguing over their theories of treatment and just what caused what, and what pills do what for what (disease.) Just put in the word civilians, or patients, where the defamation of doctors is used and you can see the similarities.
Of course it is true that many doctors have closed minds and that (many) medical schools are actually “run” by the greedy pharmaceutical and insurance companies, and/or their money, aka influence. This is a tragic occurrence in today's societies but it could not, and did not, occur overnight. I use the word societies because it is a worldwide phenomenal occurrence.
Of course the world respects money, possessions, property and power above all else. I agree that far too many doctors are not properly educated but, then, neither are lawyers, writers, accountants, engineers, scientists, etc., and the reason for it all is money. All wars are fought either over religious differences, power, money and/or the possession of lands, usually already occupied.
The reason these doctors pay little or, most times, no attention at all, to finding cures to thyroid conditions, and other diseases, is because too many of them consider themselves to be “above” the everyday, “uneducated” general public and those totally “dumb” patients, many of whom actually have the gall to “question” their diagnosis'.
Of course, I believe, that we can all agree on one thing and that is: that we are all human beings and that all human beings are, independently different, to the point that no two people have the exact same DNA (lone exception: certain conjoined twins) or will react the same way to any certain pill, or medical treatment, least of all concerning a thyroid gland that some doctors “believe” they can treat with one little, simple pill, known as Thyroxine, better known by a brand name, as T4 or Levothyroxine. This pill has a history of being pushed by certain Big Pharmacuetical companies to the point of actually having books printed and actually used (taught) in certain medical schools whereby medical students, studying for a medical degree, are taught that Levothyroxine, T4, is the only “magic pill” they need to prescribe to “cure” hypothyroidism, regardless if the “patient(s)” still even have a thyroid or not, functioning or totally removed.
The insurance companies back them (bottom line) completely and everyone is “content and happy,” as they all remember their “business classes,” and the pursuit of “happiness” (aka money, power and all the possessions their enlarged bank accounts can reward them with) as they (way too) busily conduct their business, giving their “uneducated” patients all of 5-10 minutes of their time (just long enough to hear the “right word” which will justify prescribing the “right” pill, as they, then, scurry to the next room to prescribe another pill.
May peace be upon us all and may our "enemies," as soon as God permits, soon become our friends.
Hi all, if your not converting your most likely low in selenium. That said just because your FT3 is low have you had your RT3 checked too?
Here's why you most likely have high cortisol which suppresses Thyroid hormone so the FT3 a lot of what's there is being shunted as RT3, the reason for that is you have LOW ZINC zinc is a controller of cortisol and thyroid hormone levels. If you have healthy Zinc levels the cortisol will be suppressed/controlled allowing thyroid hormone levels to rise and function as they should, no meds required.
Other metals involved are Iron and Copper they interact, odds are you could have high copper or iron these need looking at and balancing do this and the thyroid should will function normally... no meds required.. you have a metal problem...
I don't think any amount of mineral therapy will make my thyroid regenerate but I do find the high iron re absorption interesting. Will look into that.
Diogenes gave much food for thought re the concern over T3 replacement impairing the body's ability to convert synthetic T4 to T3, in the sense of possible permanent impairment of the mechanisms involved because they have been suppressed by high doses of thyroid hormone therapy over a long period. It's worth scrolling further back up the posts to see what she says.
Many thanks for all your contributions, and especially those of you willing to share your knowledge and expertise. I'm away at the moment and the huge thread has outgrown my phone's navigational dexterity. Looking forward to catching up up on my desktop.
converting of T4 to T3 then if one takes 100mcg. of T4 what percentage of the T4 converts to T3? Any ideas,...
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