Can our bodies convert liothronine T3 to rT3. - Thyroid UK

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Can our bodies convert liothronine T3 to rT3.

Angelic69 profile image
30 Replies

Hi all have been feeling exhausted even now that im taking T3 aswell as T4 and was wondering if maybe I was converting to rT3.

Feeling tired about four hours after taking 125mcg levo with 5mcg T3, body very heavy, eyes struggling to keep open just want to sleep all day. No motivation and feeling quite low. Vits and mins all at good levels.

Have had stop over at hospital as kept going to pass out and low blood pressure which they refered me to cardiac clinic so not sure if its that or my thyroid, although bloods for thyroid came back ok, Tsh had came down to 2 from 7, what do you think is going on with me.

I have had to give up all my exercise classrs and even struggle to ride my bike on short journeys now, I feel so house bound.

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Angelic69
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greygoose profile image
greygoose

No, absolutely not. T3 can only convert to T2. T4 converts to T3 and rT3. But, even if you had high rT3, it wouldn't cause the symptoms you're describing, it is inert.

However, with a TSH of 2, you are under-medicated. When on thyroid hormone replacement, it should come down to 1 or under - especially when taking T3 - although 5 mcg is only a small dose of T3. Have you had your FT3 tested?

If your FT3 is low, you should be cutting back on the exercise classes, anyway. You don't have enough T3 to sustain them.

Angelic69 profile image
Angelic69 in reply to greygoose

My tsh was at 7 about three , four weeks ago the T3 has brought it down quite quickly but they didnt mention my free T3 but i guess it was low if they prescribed T3.

Why am I struggling to keep eyes open, it drains me to try to keep them open.

greygoose profile image
greygoose in reply to Angelic69

Affects on symptoms are rarely instantaneous, even when taking T3. Maybe you're not taking enough T3, yet. Nothing will help if you don't take enough of it. But, without an FT3 result, it's impossible to say.

Also, with a TSH of 7, it wasn't possible to know how well you converted, and you probably needed an increase in levo.

Angelic69 profile image
Angelic69 in reply to greygoose

Any increase of levo than 125mcg and my eyes are looking like those eyes you see with graves disease and my mental health suffers hugely so wasnt an option.

greygoose profile image
greygoose in reply to Angelic69

So, you were taking 125 mcg levo and had a TSH of 7, is that right? Even so, they should not have added T3 without testing the FT3. What was your FT4 on 125 mcg levo?

Angelic69 profile image
Angelic69 in reply to greygoose

They would have known my free T3/T4 level, I just didnt ask for results or didnt remember results.

I had been feeling more and more exhausted on 125mcg levo, I asked if I had been given a placebo as usually I feel better than that.

I was bed ridden and had zero strength,

My pharmacist friend told me there were problems with teva and sourcing raw ingredients for levo, maybe other pharmaceutical companies had trouble too, thats the stuff you dont normally hear.

greygoose profile image
greygoose in reply to Angelic69

Oh, that is not a given. Never just assume that a doctor knows what he is doing where thyroid is concerned. Which is why we should always get a print-out of our results.

It's true that a lot of people have problems with Teva. But it does suit some people. The trick is to find the brand that suits you, and stick to it.

Angelic69 profile image
Angelic69 in reply to greygoose

I hope my doc knoqs what he is doing, funny enough it was his understudy that argued that I should be on T3 at my last endo appointment. The doc was happy with T4 only but because of cost only. GP not allowed to prescribe even now that endo has put me on it.

Teva have had a fire rhats why teva had to get hold of now.

greygoose profile image
greygoose in reply to Angelic69

That's not the sort of problem I meant. I meant that Teva makes a lot of people ill.

Angelic69 profile image
Angelic69 in reply to greygoose

I was one of those people but body tolerates it now.

SlowDragon profile image
SlowDragonAdministrator

Taking any dose of T3 (even a tiny dose) will significantly lower TSH

Absolutely essential to test FT3 and FT4 on any thyroid hormones, but especially on any T3

most important results are FT4 in top third of range and FT3 at least half way in range, but often need it higher...but still within ranges

It's common to need 2 or 3 small doses of T3 through each day

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if Thyroid antibodies are raised

Have you had vitamin and antibodies tested?

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and fasting. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Last Levothyroxine dose should be 24 hours prior to test, (taking delayed dose immediately after blood draw).

If/when also on T3, make sure to take last dose 8-12 hours prior to test, even if this means adjusting time or splitting of dose day before test

Is this how you do your tests?

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies or all vitamins

thyroiduk.org.uk/tuk/testin...

Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have special offers, Medichecks usually have offers on Thursdays, Blue Horizon its more random

Lilian15 profile image
Lilian15 in reply to SlowDragon

I think you mean the other way round. FT3 should be in top quarter and FT4 can be in middle.

SlowDragon profile image
SlowDragonAdministrator in reply to Lilian15

on just Levothyroxine we usually need high FT4 to get high enough FT3

On Levothyroxine plus T3 it's important to keep both FT4 and FT3 high enough. Many people find they need both in top third of range

T3 often needs to be in 2 or 3 small doses through the day

Lilian15 profile image
Lilian15 in reply to SlowDragon

Yes of course. I was only thinking of when taking T3 or NDT.

SlowDragon profile image
SlowDragonAdministrator in reply to Lilian15

FT4 is often low on NDt

Obviously FT4 often extremely low if on only T3

But on Levothyroxine plus small dose of T3, many of us find we need FT4 at good levels as well as good levels of FT3.

Levothyroxine plus T3 has advantage that is flexible in that you can adjust each dose separately

LAHs profile image
LAHs

Yes, T3 can "reduce" to reverse T3. There is a brilliant paper by Greg Kelly, it is called "Peripheral Metabolism of Thyroid Hormones: A Review" it's a bit heavy going especially if you don't have a biological background. It took me about a month to slog through it but once you do it will explain the whole metabolism and chemistry of the complete sequence of the thyroid selenoenzymes T4 and T3.

T3 will have an affect on your heart - but in an opposite way to that which you are reporting. Usually it will make your blood pressure (BP) rise and that rising will make you exhausted because it is like running your car engine too fast, i.e. your pulse (bpm) will be too fast, However, you are reporting Low BP and that is curious and beyond my scope of understanding.

However, high rT3 is pretty irrelevant. A TSH of 2.0 is higher than optimal (which should be about 1.0). This is a tricky one Angelica, you have symptoms of over medication (exhaustion) and under medication (high TSH and low BP). Other than this I cannot tell you more. Let us know what your doctors have to say.

Angelic69 profile image
Angelic69 in reply to LAHs

Thanks for that explaination as to why I was feeling so exhausted, I was expecting more energy with the added T3 so was a little disapointed that I still felt tired but now how you explained it makes perfect sense. Will this always happen as long as im on T3, like ive over done things even at rest.??.

As for the bp, just before they let me go home my bp was low, I did not take my medication into hospital with me and although they gave me T4 whilst I was there, they did not give anyT3 and maybe thats why it was low. I had done nothing apart from rest on the bed, but I will try to remember to ask next time I see the doc.

Do you think when my Tsh is 1 or below my energy will be better, even on T3.

My constipation is only relieved if I take 3 tbsp of live yoghurt, if idont take it nothing is moving despite my dose. Why,??.

greygoose profile image
greygoose in reply to LAHs

Can you explain how T3 'reduces' to rT3? For T3 to become rT3, one iodine atom would have to change places. I don't see how that is possible - and that certainly isn't my definition of 'reduce'. For me, 'reducing' T3 would be to remove another atom of iodine, which would make it T2.

LAHs profile image
LAHs in reply to greygoose

Yes, when I can find the paper again. I thought it was in Greg Kelly's paper but I agree, it is not.

I was not using the word "reduce" in the strict chemical sense, that's why I put it in quotes, maybe "change" would have been a better word - but that's a bit non committal.

You know, when I did not find the explanation in Kelly's paper my heart sank because it's been years since I went manic and dug into all this, I knew this would come back to bite me and dear wise one GG, you never let us down do you. If I can find the discussion again I will post right here and until then, you're winning.

greygoose profile image
greygoose in reply to LAHs

All joking apart, I look forward to reading it. :)

Angelic69 profile image
Angelic69 in reply to LAHs

Still even without official papers your explanation fitted my symptoms and I thank you. Fingers crossed you can find discussion for GG.

helvella profile image
helvellaAdministratorThyroid UK

LAHs

Afraid I don't see that at all in that paper! :-(

All mentions of "reduce" that I could find were referring to relative quantities rather than saying that rT3 could in any way be reduced to T3 or any other form of inter-conversion.

humanbean profile image
humanbean

Feeling tired about four hours after taking 125mcg levo with 5mcg T3, body very heavy, eyes struggling to keep open just want to sleep all day. No motivation and feeling quite low.

I don't think this problem you have is related to your Levo. I think it is related to a normal change in the body around lunchtime or shortly after lunch that everyone gets. Unfortunately, there are certain conditions that can make the effect become extreme, and these conditions are possibly more common in people with thyroid problems.

You might find these links of interest :

en.wikipedia.org/wiki/Postp...

en.wikipedia.org/wiki/Postp...

My suggestions about what might cause your problems :

1) Low blood sugar / hypoglycaemia. What do you eat, when do you eat, and do you eat enough? Are you trying to lose weight? If yes, how?

2) Insulin resistance. Note that insulin resistance may set in long before people become officially Type 2 diabetic.

I'll leave the explanation of insulin resistance to an expert :

thenoakesfoundation.org/nut...

3) Cortisol problems. Having the wrong levels of cortisol (either too low or too high) may cause the symptoms you are describing. There is a connection between cortisol and thyroid problems. The body uses cortisol as a substitute for thyroid hormones when thyroid hormone levels are low. Levels of cortisol will initially go high which makes people feel awful and then, eventually, in some people the adrenals glands can't keep up and cortisol starts to drop. Low cortisol makes people feel awful too. Unfortunately there is a lot of overlap in low cortisol and high cortisol symptoms, so the only way of finding out which you have (if either) is to do a saliva cortisol test. If you were to do this it would be for your own benefit because doctors only take notice of morning cortisol blood tests.

Personally, I would suggest looking at your diet first. It is the most likely cause of your problems and the thing you have the most control over - you don't need your doctor's permission to change your diet!

Angelic69 profile image
Angelic69 in reply to humanbean

Breakfast I have bran with semi skimmed milk, followed by two boiled eggs and toast. Lunch usually cheese, ham salad on wholemeal followed by live yoghurt. Tea usually protein soups with beans, kale, lentils ect.

I eat a fair amount and im not trying to lose weight and I havent lost any either.

I heard that sometimes people can become resistant to dose and maybe that was me. I was thinking it was my heart that was the problem and maybe not thyroid related. Heart problems can cause low energy and heart problems run in my family.

humanbean profile image
humanbean in reply to Angelic69

If you are prepared to experiment you could try a low(er) carb diet. This would involve you eating lower levels of carbohydrate than you do now, more fat (of the healthy variety, not something that is made in a laboratory) and more protein.

dietdoctor.com/low-carb/fat

For someone with your symptoms, if you wanted to try it, I would suggest making the change relatively slowly. I did a "big bang" switch to a ketogenic (very low carb diet) and couldn't cope with it, so I've had to slow down on switching to lower carb. I felt as though my brain and body just ran out of energy. I am convinced that my body has to learn how to extract energy from fat. It is something that my body probably hasn't done much throughout my life because I've supplied it all the sugar and carbs it needed for instant energy in the form of glucose.

The reason I was interested in your post is because I suffer from the symptoms you describe - not every day, but enough to be embarrassing, annoying or terrifying depending on where I am and what I'm doing. I am very familiar with that feeling that someone has attached heavy weights to my eyelids and the rest of my body, that I can barely climb the stairs, that I am as weak as a kitten. And the scary thing is that it happens so quickly - there is little or no warning. I suddenly feel like I've been given an anaesthetic. I have been hit with this problem while driving on a motorway. There was no escape from the motorway for several miles and I was terrified. I'm lucky that nobody died that day.

I have started making a (much slower) change to a lower carb diet and I think it is helping. My biggest problem is that I'm a sugar and carb addict so falling off the wagon happens frequently - although I'm gradually reducing the number of times I slip. I am not diabetic, although I did, briefly, become pre-diabetic. I've managed to reduce my HbA1c back into the "normal" range now.

It is possible to test whether or not you are insulin resistant. I've never done it myself, but I keep wondering if I should. I'm not clear on what the right set of tests would be to test for the condition though.

If you are interested the Diet Doctor website is well worth browsing, as is the Real Meal Revolution website :

dietdoctor.com/

realmealrevolution.com/

If you don't want to lose weight you can still use both websites. The ultimate aim is to be healthy, losing weight is optional.

Angelic69 profile image
Angelic69 in reply to humanbean

Yes I can also see my own carb addiction and agree with you that a slow approach os wisest as myself have gone back to carbs many times. Trouble is I love breads of all kinds and can almost feel the energy rush go through me when I have some after a break. I do need to cut back and hopefully im back on track and these links will keep me focused. I have taken chromium in the past but when I ran out I didnt bother to replace, silly of me really as they did make a difference with my eyes. Have you tried chromium.

humanbean profile image
humanbean in reply to Angelic69

I have taken chromium. I read it was supposed to be good for helping the body to control blood sugar, and was supposed to reduce carb cravings. I don't take it all the time, just for the odd week here or there. I'm never sure whether it is doing any good or not!

Angelic69 profile image
Angelic69 in reply to humanbean

Thanks for links, they make sense. Should be cutting carbs, cholesterol was high 😄

greygoose profile image
greygoose in reply to Angelic69

Cholesterol is high when T3 is low.

Angelic69 profile image
Angelic69 in reply to greygoose

Ive just heard carbs are what increase cholestrol, high carb diets

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