I had some questions out of curiosity about conversion issues I've tried to research but had no luck and so wondered if anyone on here might have an idea! If someone has a conversion issue due to any number of issues like low vits/mins, underweight, low calorie diet etc and is put on combination therapy t3/t4 or ndt etc due to the low conversion without fixing them first, if the conversion problem was then 'fixed' by remedying the issues would the dosing/need for T3 change? Also regarding levels - when I was started on T3 I was on only 75mcg levo but that took me up to 85% of the range and with a T3 only 16% through. I am curious - does the T4 remain so high because it is not converting and if you started converting would the T4 level drop and T3 rise? In which case if you were on T3 alongside the T4 would you possibly see T3 go too high with newly corrected conversion and have to reduce it? Really interested to know if anyone has any knowledge on this.
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There's a lot of supposition here and ifs and buts. With thyroid being such an individual thing there are no definitive answers.
If a person added t3 to levo when there vitamins were low there is no guarantee that they would get the full or much benefit from the t3.
If a person improved their conversion or if they had some sort of physical change then yes their needs for replacement hormones might change and doses altered.
Taking t3 tends to lower ft4 and suppress tsh.
The t4 doesn't stay high because you are not converting--it is at that level because you are taking t4 hormones that result in it being at that level.
If you have hashis then you can also add whatever your thyroid puts out into the equation.
There is an interdependence between t4 and t3. Changes in either affect the other. When you are on a combination therapy then you need to adjust your ft4 and Ft3 levels to suit your individual needs. This is only managed through slowly changing levo or lio one at a time in small steps and close monitoring of symptoms and bloods.
Thank you for the super detailed response! That's really helpful to know about the T4 remaining high even if you are converting! Despite how awful hypothyroidism I do find it all really interesting. I still think it's mindblowing how sensitive our bodies are to some hormones!
I said that to my (good) doc once - the bit about how very sensitive we are to variations in thyroid medications. He said with great irritation, " SOME people are and you are obviously one of them!" I take it he was annoyed that he didn't have a patient who he could just palm off with Levo and they went away happy for the rest of their lives. I drove that poor guy crazy, but he was willing to learn a lot and interested in things thyroid so we both staggered through the whole process together - with a good outcome for me.
Your first blood test when you were not taking hormone suggests your pituitary was underperforming (strictly speaking your thyrotrope - the bit of the pituitary that produces TSH). This is probably due to your hypothalamus producing too little TRH - TRH stimulates the pituitary to produce TSH.
Your TSH is far too low for your fT3, fT4. Nomally as fT4 falls TSH rises dramatically and stimulates the thyroid to produce more T3 and accelerates the rate of T4 to T3 conversion. This allows the patient to maintain mid-interval fT3 levels. This is why may people with a TSH of 5 or 10 have no symptoms and are fine (although may be at risk for some conditions).
Central hypothyroidism is a term used for a more serious condition where TSH is very low and other pituitary hormones are usually affected. Most endocrinologists would not accept that you have central hypothyroidism. That's the way the term is used. I use the term 'subnormal TSH secretion' to describe your situation, it describes what is happening.
There can be many causes of subnormal TSH secretion, such as low calorie intake or concurrent severe illness (referred to as NTI: non-thyroidial illness). Many doctors (not yours) will dismiss a patient with NTI saying the thyroid is behaving as it should do. This is nonsense, if they can't cure the underlying condition they should treat the hypothyroidism.
To answer your first question if you fix the underlying problem that is causing hypothyroidism or impaired deiodinase (conversion) then of course the need for T3 would be reduced. This doesn't happen very often from what I've seen. (I'm a patient not a doctor).
My view is subnormal TSH secretion has two effects. 1. There are abnormally low fT3 and fT4 levels, even if both are within their reference intervals. 2. TSH stimulates deiodinase, especially type-2 deiodinase (D2) which converts T4 to T3 in organs such as the brain.
The serum levels of fT3 and fT4 can be restored by taking a combination of L-T3 (liothyronine) and L-T4 (levothyroxine). However, the brain relies on D2 to produce 80% of its T3 by converting T4 to T3. The evidence suggests this is dependent upon TSH stimulating the conversion of T4 to T3 by D2. When TSH is abnormally low this will not happen, the blood fT3, fT4 levels may be fine but brain T3 levels will remain low. You need extra T3 in the blood to compensate for reduced brain T3. This is potentially a risk of having too much circulating T3 but I have not found a problem.
As far as I know no endocrinologist has ever considered this. A low TSH will reduce brain D2 activity leading to brain hypothyroidism.
From a practical viewpoint I have found that it's important to split my L-T3 doses and when the dose is about right I am able to get to sleep OK and tend to sleep well with vivid dream. If my dose is too high I am alert or even wired at bedtime, if it is too low I wake up many times and my dreams are fuzzy. It's important to take some of your L-T3 at bedtime, the brain works hard during sleep. Growth hormone is produced during deep sleep and is needed to repair micro-trauma which can lead to aches and pains. Good deep sleep is essential.
I would take a magnesium supplement (away from thyroid tablets) as this will steady the heart and relieve constipation. I take magnesium citrate but some other forms are also good. Magnesuim oxide and hydroxide are useless.
In non-thyroidal illness and very low calorie diets the hypothalamus stimulation of the pituitary is reduced, there is less TRH (no blood test for this). This is in order to slow the metabolism to protect the body, from severe illness or starvation. Another occasional cause of subnormal TSH secretion is Hashimoto's. There can be a period of hyperthyroidism which the patient may not notice. This supresses the TSH and if this goes on for many months the hypothalamic pituitary thyroid axis can become 'down-regulated' - the axis gets stuck in a reduced mode, TSH stays low even after the period of hyperthyroidism has ended. Sometimes this resolves sometimes it doesn't.
From your point of view I would supplement with magnesium if you don't already do so. Magnesium citrate would be good for you because it is well absorbed but also has a bit of a laxative effect. Mangesium protects the heart and can correct some minor defects due to deficiency. Note that magnesium blood tests are no use, they do not show intracellular levels which is what matters. Just supplement. Make sure you take some of your L-T3 at bedtime.
I don't think you will get much better until you are on higher doses of L-T3 although you can't tolerate this at the moment. The magnesium supplementation may help after a few months. Rarely patients have adrenal insufficiency which makes it difficult to tolerate thyroid hormone, this usually resolves after a short while. It's unlikely you have this as you tolerated 75 mcg levothyroxine, even if it didn't help.
You do suffer from orthostatic hypotension (dizzy on standing). Your endocrinologist or GP can check this out by measuring your blood pressure lying down and then standing up. Low magnesium can cause this as the blood vesciles respond to intracellular magnesium levels. It can also be affected by other factors such as diabetes (unlikely as you are slim) or low aldosterone which is an adrenal hormone. I wouldn't worry about your dizzyness on standing unless it is pronounced.
I would try magenesium if you are not already doing so. Carry on eating, whatever you like and agrees with you. Soluble fibre such as oats or soft fruits are good for constipation - not bran. If you can increase your L-T3 that would be good, at least make sure you take half at bedtime.
If your problem was caused by calorie restriction you might find you don't need to take any thyriod hormone eventually. You haven;t gone on a very low calorie diet in the past? The most likely scenario is that you had Hashimoto's a few years ago, went hyper without noticing it and it down-regulated your axis leading to a subnormal TSH.
Wow thank you for this amazing response! I am really fascinated by this whole thing - its super interesting what you have said about potentially having had a period of hyperthyroidism in the past - my endo originally said he believed I had central hypothyroidism but last time I saw him he said he believed I have hashimotos. I am 23 but he believes I have had this for many years - interestingly when I was 16 I had a period of very very bad anxiety and I am wondering if that could have been a factor! I had rock bottom ferritin and b12 back then too. Never been on a low calorie diet by choice until my hypothyroid induced gastroparesis late last year and I had been on thyroxine for a couple of months eating normally before that happened - I don't think my conversion is likely to change I was just very curious about it all! Thank you again so much for the detailed response and teaching me so much!
Can you expand on adrenal insufficiency affecting thyroid hormone please? I have adrenal problems following massive doses of steroids to prevent an organ rejection, and now am having a bit of difficulty increasing my Levo - having to do in it minuscule doses to stop feeling jittery. It's working slowly, my energy levels are coming up and other symptoms much better (gastro symptoms and fibromyalgia) but am amazed at how tiny the increase has to be. thank you!
Long term severe hypothyroidism can weaken the adrenals leading to adrenal insufficiency. This is a very rare condition but if these patients are started on large doses of thyroid hormone they could go into an Addisonian crisis. These patients are started on a low dose of levothyroxine and may receive an adrenal hormone such as prednisolone for a short time. The adrenals recover once the hypothyroidism is treated.
Your case is rather special and could be explain your difficulty with thyroid hormone. The usual approach might be to give you a little prednisolone or similar to help but perhaps this might delay the recovery of your adrenals. This is total guesswork on my part, I have no knowledge of adrenals. Maybe you just have to take it very slowly, it's worth mentioning to your doctor.
thank you for taking time to reply - I have tried endriconologists etc but they say the only way to help my adrenal gland is by taking yet more steroids, which I refuse to do. Its not an acute situation (though if I have a car crash or something I am supposed to tell docs to they can supplement with steroids so I don't go into crisis). So I am just trying to balance things out by supplementing vitamins and increasing my thyroid by tiny doses, as although I've been on 100 mg of levo for 15 years, private tests show I now need more. Going up by crumbs seems to be working - I want to get to 125mg eventually, but happy to take my time. I'm assuming things will balance out eventually, and the slightly hyper feelings will reduce.
I have no knowledge of adrenal issues but your approach seems very reasonable. Do you need to wear one of those bracelets / pendants that states you have adrenal issues in case of an accident?
yup. By the way, sorry to keep on at you but you seem so knowledgable - I am finding that as I increase I seem to be getting quite a lot of 'brain fog' and having a bit of trouble finding words - not sure if that's thyroid related or just general stress over the current crisis! I'm usually pretty sharp!
As noted earlier increasing levothyroxine can reduce TSH and hence fT3 leading to brain hypothyroidism. It's just a matter of judging what dose is best for you.
Just to jump in thats very interesting what you say about levothyroxine. As I hadn't been able to deal with 15mcg my endo agreed to try raising levo by 12.5 instead however I am 4 days in and worse than I was trying before and when I tried to raise t3 - I've got my usual too much hormone headache (which I didn't even get on 15mcg) and my heart rate has gone up to 88 highest its ever been. Making me think maybe the problem for me is Levo not T3 and that I need to decrease my levo and up t3 instead!
Very interesting! I had posted many times about my shakes which were very upsetting and when I did a saliva test I discovered I had early phase adrenal dysfunction. I had gone through a prolonged period of stress and hadn’t been eating well due to loss of appetite (and my TSH has been suppressed leading to my endo refusing to increase my meds) so your explanation is very interesting to me!
As an aside....Very interesting about magnesium and orthostatic hypotension which I have suffered from for some years. It was especially bad pre diagnosis (atropic autoimmune thyroiditis)and was pretty bad on Levothyroxine, improved on NDT but I still get occasional episodes of it, also horrible cramp. I am trying simethicone as you mentioned it, and I’ve started magnesium malate 2x 116.7mcg daily - would that be a helpful dose to deal with the orthostatic hypotension and cramps in your opinion? I have taken quinine for the cramps - it stops them fast but no idea why it works. Doc suggested magnesium, but did give me a prescription for quinine. It took me a while to get any magnesium. I don’t take the quinine very often because the cramps are intermittent and I use it as a last resort if it becomes unbearable.
I've no experience of magnesium malate, I take citrate up to the dose recommended on the bottle, although I don't take it very often now. Interesting about the quinine.
They say 3x 116.7mcg on the bottle as the daily dose. Thrice daily dosing has defeated me so far. Mag malate is derived from fruit & supposed to be reasonably effective . It does not affect the guts or bowels like some other forms. The quinine is an old treatment for cramp and it works in a couple of minutes to stop it in its tracks in my experience. I had IV quinine for p. vivax malaria it put a stop to that too. It’s one of my favourite medications - it never caused side effects like ringing in the ears. The doc that gave it to me for the malaria warned me it could make me feel worse, to which I wryly replied - if I felt any worse than this I’d be dead! I was not joking either. I prayed to die the aching, headache etc was so excruciating. I was rather surprised to actually wake up again the next day and as a bonus to feel considerably better bar having a serious deficit of red blood cells so the slightest exertion was completely exhausting. It’s a nasty illness. The students did well out of it I allowed them to see me because I was a real live classic case of malaria. During fevers they were amazed how hot my forehead was, they did not need to even touch it just hold their hand above whilst exclaiming that the heat coming off was incredible. They also saw me the next day after the quinine treatment. I don’t think they use it anymore. Good to do your bit for medical science!
Apparently Quinine may help by decreasing the excitability of the motor end-plate and increasing the muscle refractory period according to a paper that then goes on to list a scary load of potential side effects and suggest stretching is a better cure - I beg to differ and seem to tolerate it well! I might take one tablet every two months or so.
I don't know my present levels as I dose by symptom. I've definitely needed less thyroid hormone overall since I started regular injections of B12. I assume I needed that to begin with to better utilise the hormones I was taking.
Am the same as. Badhare, once I went onto B12 injections I noticed I needed a slightly lower dose of thyroid meds after a while. My B12 was low but in range but had caused mutiple symptoms of b12 deficiency, including neurological. So its definately worth making sure your vits & minerals are optimised to ensure you maximise the thyroid hormones you are taking.
In my experience the biggest issue for conversion outside of our genetically fixed points is excess levothyroxine.... split dosing to no more than 50 mcg in any single dose at 6 hour intervals increased my ft3 levels. Excess t4 reduces intercellular rate of conversion and increases reverse t3.
Hi hashi i was reading along this post and wanted to chime in..i have high rt3 32.5(0-24) free t4 is 1.6 (0.8 -1.8)tsh 0.1(0.4-4.2)freet3 5.8(2.2-4.4).and been feeling hypo and hyper mixed i lowered my ndt and added t3 17mcg spread out during the day..temps been 98.6 when waking and theough the day depression is bad eye twitching, achiness n my bones could you give your advice on this thanks
Hi Netty all I can say is from my experience and reading of what constitutes normal for most people is that you’re significantly over replacing thyroid.... 17mcg liothyronine t3 would blow my socks off. And you’re taking NDT?!? Your body may be suffering the imbalance and is clearly trying to decrease free t3 through negative feedback loops. Could you try to increase t4 with levothyroxine and cut your total t3 to nearer to 10mcg (from all sources) or do you have a clinical need for suppressing TSH? even so the symptoms you experience are indicative of excess replacement when the body’s response feels both hypo and hyper, in my experience anyway. Of course adjustments should be gradual but the optimum is predominately t4 replacement with just enough t3 to keep levothyroxine doses moderate eg 75-150 mcg t4 depending on individual physiology
There are widespread references to the negative feedback of free T4 on deiodinase activity and so far as my own experience goes simply trying different regimes and taking monthly blood tests and keeping a symptom diary.
You can see why it takes so long to find a perfect dose and why we all have such different needs! I also keep a small diary of symptoms every day and it's been helpful for seeing how my body responds to t3 and t4!
There are three things which affect your T4 to T3 conversion:
Vitamin levels
Selenium level
T4 level.
I am assuming you have brought all of your Vits. up to par.
If any of those are deficient you will not convert (so you will need external T3)
What I would do is this:
T3 has a short half life (8 hours, (some say 24)). Stop taking this for a few days then measure your fT4,fT3 and Selenium (Se) levels. This is your base line.
If your Se is below par that is the reason you are not converting (Se is the catalyst for the T4 to T3 reaction). If you are deficient, take Se either as a supplement or via diet (I do the latter). After about a week measure your fT4, fT3 and Se again. That may have solved the problem. If it did not:
Maintain that intake of Se but raise your T4 dose. I found that once I got to a dose of Levo to a certain high level (~ 137mcg - 150mcg) I suddenly started to generate T3 - it seemed that my T4 dose had to cross a threshold before I generated T3. And I felt really well btw. Now at this point your doc (as did my Endo) will say, "Whoooooo your TSH is too low, drop your Levo down" that is what my (stupid) Endo said and that was the end of my experiment - because I hadn't been long off my TT, knew no biology at all and thought she knew better (she didn't)
Anyway, if you have reached a high T4 dose and your Se is adequate and you still have not generated T3, then you will need external T3 - which I understand you are taking.
But anyway, it's worth a try, if you can generate your own T3, life is simpler.
Oh and you wrote above that you found all of this Thyroid hormone stuff fascinating. That's the spirit! That alone will get you through. Fascination is all I had, I had never had a biology lesson in my life, I avoided it like the plague (because I heard you had to cut up frogs) so I stuck to physics. But stay fascinated and you will solve your problem.
Thank you for this response! I was hoping I could generate my own T3 but I don't think it's to be unfortunately - I was previously at 88% through range and my T3 went up by only 1 ( from 3 to 4 in the range of 3.5-6.5) with 75mcg levo so to get it anywhere near optimal I would be hugely over range in T4. Nevertheless I had hoped since my vits and mins became optimal that I might be able to produce it at a higher level but I tried increasing levo instead of T3 and it caused headaches and anxiety so I think that levo may be my issue. I have to say the low TSH thing that doctors/endos parrot confuses me hugely - I have secondary hypo so my TSH was already 1.7 before starting treatment and becomes suppressed on any hormone. If they wanted me to maintain a normal tsh I wouldn't be taking any thyroid hormone and I would still be extremely ill with T4 and T3 under range!
You raise another factor. Anxiety suggests high blood pressure (BP). This is something else to measure while you are adjusting your doses. High BP goes along with too high T3. When you get to the point where you feel well because you are generating optimal T3 then you have to make sure it is not done at the expense of your BP. If you get to that point you have to give your heart the priority - and drop your T3. This is the state I am in. When I raise my T3 to the point where I feel great like super woman my BP is sky high so I have to drop back to being just fit and healthy and glad of it. I do fall asleep about 9:00pm, so no more late night parties but I can live with that - at my age most people are not going to late night parties anyway.
Luckily I had my blood pressure done at the hospital a few weeks ago when I was feeling very bad and it was low normal - lower than it was before I started treatment!
Yes it’s fair to say you have to boost t4 to beyond physiological norms to push free t3 conversion to anything like normal but the resulting ft3 / tsh levels may not be entirely benign even if symptoms resolve. For example there are academics who suggest tsh also influences more widespread thyroid signalling and that overt suppression may affect this, plus the long term effects on things like bone density and cardio health are unclear. Perhaps some people can manage or thrive on high t4 low tsh and it’s certainly easier to replace than the faff of getting and using t3 replacement. But for me at least, 150 mcg of levothyroxine makes me feel worse than 112mcg levothyroxine and 5 mcg liothyronine even though the blood test results appear equally acceptable, albeit with top of the range ft4 and bottom range tsh on levothyroxine only. But lab ranges are not our range!
I am beginning to believe I am in the same boat - I thought my issues were with T3 but I think its too much T4 thats the issue for me as I tried to increase levo instead of T3 and it gave me awful headaches and anxiety. I never got any response from 75mcg of levo and just 10mcg of T3 changed my life. I do wonder how much my issues with T4 could be related to the fact I already had a low TSH due to having secondary hypo. You can see how our different situations can impact are needs so much and why the very concept of a one size fits all approach to thyroid treatment is ridiculous
Good points, I agree that the long term effects are unclear. But, you know, I have been hearing that since I took an interest in all things thyroid after I had a TT about 15 years ago. This suggests to me that the lack of clarity on this subject should have been cleared up by now. If you are in the medical field perhaps you could go to the orthopedics department and ask for (anonymous) data on patients whose bone density and their TSH have been measured about the same time. Look to see if there is any correlation between the two.
I ask this because I do not appear to have any reduction in bone density over a slight reduction normal to age and my heart is fine, my TSH has been .003 mIU/L for 15 years. I do however have reduction in cartilage in my knee. I was worried and asked my "arthropod" if the lack of cartilage varies with bone density. He said, "Not at all, in fact you can have very high density bone with very low density cartilage and vice -a -versa!". I should have asked there and then for the patient data but I did not. I will try again but he probably will not give it to a random patient (me).
If you could get hold of such data I am sure hundreds of people on this site would be interested.
Maybe 15 years isn’t significant in the TSH bone density equation ?.... I was 50 when I started on levothyroxine and if I suppressed TSH to get adequate t4t3 conversion until I’m 90 when bone density may be an issue anyway I wonder if there could be a hazard in this and whether it’s better to simply avoid unphysiological side effects if at all possible. I’m not aware that any properly organised raw data is available to answer the question in a meaningful way. Sometimes conjecture is as a good a basis for sensible action as any collection of small scale or retrospective research.
Yes, it would take a search and some organizing, I would love to do it but I would not be allowed to access raw data (with names on it). I will email my arthropod, he just might do it for me since he isn't in the infectious disease department (ie a lot of time on his hands since all elective surgery has been postponed).
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Conversion problem
Does anyone NOT have a conversion issue, but still have low FT3??
T4+T3 combo
An update to recent post 'Is this a conversion issue'?
Where does T4 to T3 conversion take place?
