Hi there, I have written up more of my history in my bio but briefly, I have had an 8 year journey to get through a debilitating illness, which was diagnosed as ME/CFS and then Long Covid, even though at the same time my Thyroid was found to be mal functioning. I did ask something here a few years ago, but I had to stop looking, as when you have ME/CFS there is so many different things possible to try you don't which one to go for and I felt so ill I had to just get through each day and switch off from looking online.
But I always thought my Thyroid was a root cause and fought to increase my Levo even though the GP said my bloods were all normal. I switched GP to one who listened and would experiment with my dosing and eventually, only last year, he referred me to an NHS Endocrinologist saying that my T 3 might be the problem. During the 10 mnth wait to see the NHS Endo I saw one of the GPs recommended by Thyroid UK and started taking Liothyrine (T3) in April 24. I am now taking 100 mcg Levothyroxine (T4) and 10 mcg of T3. I feel so much better, like I have a new lease of life, but not sure the dose is quite right, hence this post.
I have also seen an NHS Endocrinologist and they have agreed to prescribe the T3 though still waiting for this with red tape going on and the original Dr having been a locum has left. They were very concerned about my low TSH as it is 0.01. The GP had prescribed 15mcg of T3 but I was waking up in hot sweats not sleeping very well and could feel my heart pounding in my chest. I got scared about this with the Endo saying how it might affect my heart.
I have now been reassured by the private GP about the TSH being low but I have reduced the T3 to 10mcg. The private GP says I can just experiment to see what works for me. I am not sure whether I should reduce the T4 and try and put up the T3 as this is definitely giving me a new lease of life, but the heart pounding and night sweats interrupting my sleep when I was on 15mcg, did not feel good for me, though I did lose weight, which I needed to, but since dropping to 10 it has gone back on.
I am wondering if I reduced the Levo would this help the side effects?
Also the times of day to take it , the private GP said 3 times 8, 12 and 3 and not after 5 pm. The NHS DR said twice 8 am and 4 pm. I want it not to affect my sleep. Someone posted on here a little while ago about T3 raising the body temperature and it certainly does for me, going up above 37 when I take it, so no wonder the night sweats. But wondering how long the affect of T 3 lasts in the system?
Basically I don't know what to do but don't feel the dosage is quite right but maybe I should let it settle for a while?
I also wondered if anyone knows how to work out the T4 to T3 conversion rate so I assess this myself?
I also have just seen that both my brands contain either mannitol or lactose, I have reacted to mannitol in a brand before and have been careful not to have it in the Levo but just seen the T3 contains mannitol even though I thought the GP has asked for one free from it. And I am trying to be lactose free, which is in the Levo, so I am also wondering if I should start the fight to get brands free from both of these additives before considering the dose as they may be impacting how I feel too?
Sorry this is long, it feels like a continuing minefield and fight and even just to be clear about what I am asking seems hard. A lot of days I don'f feel like fighting but today I got up and wrote my bio on here and posted this. So apologies if this is a bit all over the place, I appreciate if anyone has any thoughts about any of this. Many thanks in advance.
Written by
Dhalia50
To view profiles and participate in discussions please or .
First of all, when you take your T3 should be when it's best for you. There are no rules about this, and a lot of people find that if they take some T3 at bedtime, it helps them sleep - right now, I don't take my T3 at night, for various reasons, but when I did, I slept like a baby! It didn''t affect my sleep at all.
Secondly, whether or not you reduce your levo would depend on how high your FT4 is. Do you have any labs with ranges to share with us? Too much T4 could be a problem with you. But then again, so could too little. Our need for T4 is highlly individual. You have to find by trial and error how much you need as an individual. But, I don't think it has anything to do with the effect T3 possibly has on you.
How long do the effects of T3 last in the system? Longer than you might think. It doesn't run out, like aspirin. The half-life of T3 in the blood (where it doesn't do anything) is about 24 hours. That is to say that if you took 10 mcg this morning, by tomorrow morning there will be 5 mcg left, minus what got into the cells. What gets into the cells stays there for about three days. And during that time, you are continually topping it up, so in fact, the effects last for as long as you're taking T3.
As for your heart, you have to understand that doctors are terrified of T3. They don't fully understand what it is or what it does. And they don't realise that the heart needs an awful lot of T3 to function correctly. For T3 to have a negative effect on your heart you would have to be taking an awful lot of it! More than you would feel comfortable taking in all respects.
Now that you are taking T3, it is impossible for you to see how well you convert. That has to be done when on T4 only. So, if you have in your archives results for FT4 and FT3 tested at the same time, with the ranges, post them here and someone will convert them into percentages and compare them.
As for the lactose and mannitol, I don't know about either of those because - touch wood! - I'm not affected by either. But, it is said that the amount of lactose you would get in one of those tiny pills would be so small that it is unlikely to have any effect. Don't know if the same is said of mannitol, though.
Bloods when I saw Private GP in April on Levo 137.5mg OD... FT4 21.5, FT3 4.3, TSH 0.01, VIT D 55, B12 230. Dr said my conversion was @5 and very poor and too late to try and repair with diet and supplements. (I wondered if anyone can tell me how to work out the conversion rate for my interest?)
So, don't know what your doctor means by conversion being @5, but as far as I can tell, it does look poor. But to really know how well you convert we need the ranges. Results without ranges are meaningless.
Don't know what he means by 'too late to repair with diet and supplements', either. How does he know your poor conversion was caused by low nutrients? There are many, many causes of poor conversion, and if yours wasn't caused by low nutirens, then raising nutrients won't 'repair' it.
Bloods in July after being on Levo 100mcg and Liothyrine and very high dose vit D 15mcg FT4 18.5, FT3 5, TSH 0.005, vit D 84.9, B12 196
This isn't very clear. Are you saying that you're taking 15 mcg T3 or vit D?
And, once again, to make sense of it, we need the ranges.
The GP I see is a woman and recommended on the Thyroid UK list. I am just reporting what she told me, said I would need T3 rather than supplements. And she said my conversion rate was very low at 5, but I don't know what that means that was why I wondered if anyone knew how to work it out.
She advised 8000iu Vit D 8 weeks then 4000iu 8 weeks then 2000iu forever. I am now down to 2000 daily. Didn't say anything about B12.
FT4 range 12-22 FT3 range 3.1-6.8 TSH range 0.27-4.2 B12 range 145-569 250Hvit D range 50-250 Ferritin range 30-264 Mine 138
Yes sorry I corrected it on another post these results were on T3 15mcg daily.
Well, I agree with her that you need T3, just not for the same reasons.
But you need supplements anyway. Your B12 is dangerously low. But as it's within the range, and doctors don't understand ranges, she thinks it's ok. But it should be at least 550.
So, to work out how well you convert T4 to T3, what I do is convert the results to percentages of the range:
FT4: 21.5 pmol/l (Range 12 - 22) 95.00%
FT3: 4.3 pmol/l (Range 3.1 - 6.8) 32.43%
Looking at the percentages you can see there is a huge gap between the FT4 and the FT3. If you converted well, the FT3 would be just slightly lower than the FT4. But, with that huge gap there is no doubt that you are a poor converter.
And I would recommend that with such a low B12, you ask for advice on the Pernicious Anemia forum, because that's what your doctor should be testing for:
The accepted conversion ratio when taking T4 only thyroid hormone replacement medication is said to be - 1 / 3.50-4.50 - T3/T4 - with most people feeling at their best when they come in this ratio at 4 or under.
To find out how well your conversion is - you simply divide your T3 into your T4 -
so we have your T4 @ 21.50 with your T3 @ 4.30 - which comes in at 5 :
Double check - 5 x 4.30 = 21.50 :
This conversion ratio only applies when taking T4 only medication -
and only has any significance once the T4 has been built up in your blood stream and your T4 blood test result in the top quadrant of the range.
Hope that helps solve one question - without making a further 3 !!
Thank you so much for this. That makes sense as the Dr said it was 5 and I must have translated that as meaning it was low... Basically just made that up! A very easy equation for people already on T4 to see if they need T3! 🙏
Yes - 5 is wide and outside of the accepted T4 conversion ratio -
though I've seen new forum members with scores up in 6's - and having been prescribed anti depressants as a second line treatment, which don't work,
and then believe that it must be ' all in their head ' and feeling as though they are not believed but then after some explanation and a better understanding find their ' trust ' was misplaced and their relationship with this medical professional all but lost.
Sadly in primary care ' being in a range ' rather than where in the range you should feel your best - is not a recognised and maybe not taught.
Currently in primary care the doctor can't initiate a prescription for T3 to restore thyroid hormonal balance and you need to be referred to a NHS endocrinologist -
who may or may not help you -
as financial restraint rather than medical need is in place by various ICB areas throughout the country and we are up against something of a post code lottery as to whether the NHS will and can restore your health and well being or not -
forcing many forum members to self source their own thyroid hormone replacement.
as greygoose said …..timing and doses are all highly individual
Many, many members on small doses of T3 find small dose at bedtime gives great sleep
Recommended that all thyroid blood tests early morning, ideally just before 9am, only drink water between waking and test and last dose levothyroxine 24 hours before test
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)
T3 ….day before test split T3 as 2 or 3 smaller doses spread through the day, with last dose approximately 8-12 hours before test
test after 6-8 weeks on unchanging dose, timings and brands
please add most recent results
Which brand levothyroxine and which brand T3 are you currently taking
No mention of vitamin levels
What are your most recent vitamin D, folate, B12 and ferritin results
What vitamin supplements are you taking
Personally after much experimenting I split 20mcg T3 as 4 x 5mcg …6am, 11am, 5pm and 11pm …..and Levo at 11pm
Higher Prevalence of “Low T3 Syndrome” in Patients With Chronic Fatigue Syndrome: A Case–Control Study
Your current dose 100mcg T4 + 10mcg T3
I suspect you need less T4 and more T3....but we don't have any current lab results
I'm guessing you don't convert well in which case FT4 is likely too high....not a great idea it potentially causes other problems.
T3 naturally reduces TSH
I'm on 100mcg T3-only and my TSH has dropped off the scale!
GP thought I could kill myself but years later I'm still here and they now leave me to self medicate!
TSH is a pituitary, not a thyroid hormone and is basically a signal to the thyroid to produce more, or less hormone. Your TSH is telling the thyroid not to produce more hormone, it senses there is enough....but that "enough" does not specify T4 or T3!
Symptoms of both over and under medication can be similar.
The heart needs a great deal of T3, unless you overdose it's unlikely to be harmful....and 10 or 15mcg isn't going to do that
And, if your FT3 is low it can be that when you add T3 the body appreciates this because it needs it, but if not enough it signals that it needs more by raising symptoms.
Might it be that you need to give the increased dose of T3 time to settle in the system.
You may need to experiment with timinig of your dose but don't make T3 changes before at least 2 weeks.
I take my full dose of 100mcg T3 at bedtime and that works for me....but won't for every one! It's trial and error....advice which isn't too helpful I understand....been there and had to experiment!
In your shoes I'd be inclined to reduce the T4 dose , say by 20mcg ....although T3 will reduce T4...and get back to 15mcg T3
Just a few thoughts based on my own experience....hope something resonates
Doctors frequently do not understand T3 making dosing a nightmare!
Just read your bio. What a journey you have been on and yes it is encouraging. Well done for keeping going! The trouble I found with having a diagnosis of ME/CFS was that there were so many possible avenues to go down and advice and suggestions and supplement it was overwhelming and when I was at my worst even reading a post on here was too much for me let alone trying to work anything out. I could not see the wood for the trees though I had an instinct that that my thyroid function was involved. Now I know that my thyroid function is a root physical cause it makes life simpler. I suspected it all along since I first had the blood result and 8 years later I have got somewhere and now reading your bio I feel reassured that I am now at the beginning of another journey to get to the right dose and combination and I am not alone. Thank you for sharing. 🙏
I'm just reading through replies again to try and work out a plan and at the beginning of your post you say you're on 100mcg T4 and 10 mcg T 3 but later twice you say 100mcg T3... Can I just check do you rake 100 or 10mcg T3? 🤔 🙏
Welcome back! Reading your post with interest as some similarities.
My symptoms pre-diagnosis also dragged on for 8 years (although not debilitating - I send big hugs your way that you had such a hard time, but glad you’ce found new life on T4/T3). I am currently on similar T4/T3 (I am right now in the middle of going from 100 to 112.5 Levo, and have been on 10 T3 for a year.)
I am a couple weeks from my next blood test so am hoping to see if my results show I’ve overshot my dosing. I feel better than ever and whatever symptoms I have sometimes are similar to the ones you describe but my dose hasn’t settled yet so I’m not jumping to conclusions until I get tested.
I am very curious what your TSH/FT4/FT3 results are. Do you have those to share?
Thank you so much for all the replies and taking the time to do it. It is very interesting what some of you have said about taking it at night. Whereas I was feeling I needed to take it far away from night! I will experiment.
Bloods when I saw Private GP in April on Levo 137.5mg OD... FT4 21.5, FT3 4.3, TSH 0.01, VIT D 55, B12 230. Dr said my conversion was @5 and very poor and too late to try and repair with diet and supplements. (I wondered if anyone can tell me how to work out the conversion rate for my interest?)
Bloods in July after being on Levo 100mcg and Liothyrine and very high dose vit D 15mcg FT4 18.5, FT3 5, TSH 0.005, vit D 84.9, B12 196
My Cortisol level in the morning was 30... When top of range for am is 20. T3 appeared to raise my Cortisol levels and causing severe nights sweats and waking early wired and heart pounding so reduced to 10 for that reason.
Now I've found Mannitol is in this brand of T3 this may be impacting me as I had a severe reaction to it in Levo so I am trying to get Mannitol free T3, though it is three times the price, so I can rule out that affecting me.
With serum B12 result below 500, (Or active B12 below 70) recommended to be taking a separate B12 supplement
A week later add a separate vitamin B Complex
Then once your serum B12 is over 500 (or Active B12 level has reached 70), you may be able to reduce then stop the B12 and just carry on with the B Complex.
If Vegetarian or vegan likely to need ongoing separate B12 few times a week
Thorne Basic B recommended vitamin B complex that contains folate, but they are large capsules. (You can tip powder out if can’t swallow capsule) Thorne can be difficult to find at reasonable price, should be around £20-£25. iherb.com often have in stock. Or try ebay
IMPORTANT......If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 5-7 days before ALL BLOOD TESTS , as biotin can falsely affect test results
In week before blood test, when you stop vitamin B complex, you might want to consider taking a separate folate supplement (eg Jarrow methyl folate 400mcg) and continue separate B12 until over 500
Post discussing how biotin can affect test results
Today I took 5mcg at 8 and 5mcg at 8. I certainly did not notice any adverse symptoms without taking it through the day and may even have felt calmer. It was the private GP who told me to front load the T3 and take it 3 times a day 8,12 and 3 and not to take it after 5pm or it would affect my sleep. So I will see how my sleep goes but I feel hopeful after having two nights of only 5 hours and my heart pounding. My resting heart rate has gone up from 60 to 80 since starting the T3 and I can feel it pounding but this has eased since going down to 10mcg T3. I am now wondering if taking the T 3 over only a few hours in the day is what is affecting me, that makes sense to me and why the impact is happening at night... well I shall see over the next few days.
I also recognise that some of what I am feeling may be due to the Mannitol. I can feel it in my lips and I assumed that was the T3, because I assumed the brand I was taking, that had been prescribed by the private GP, who I had told I had reacted to Mannitol in the Levo, would not have Mannitol in it! No leaflet came with with the pot.
Everything just feels so difficult, even the people I am supposed to trust, and pay a lot of money to, I can't, it would seem. So hard to keep going but much easier now taking T3, without it I could not have engaged with all of this discussion, my brain fog was so severe. I only have 3 days left of T3 and unlikely to sort out prescription for one without mannitol but I have some Amour as I tried that but didn't find it as effective but it will be better than no T3. So at least I don't have to worry about that.
I have just read your bio, what a journey you have been on. Thank you so much for sharing all the knowledge you have picked up along the way. 🙏
I'm just going over replies again to work out a plan. When you say last dose T3 8-12 hours before blood test... Do you mean it's better to take it nearer the test? As if I take T3 as I have been it might be 18-20 hours before blood test. 🤔🙏
Oh thank you for this. My private Dr was giving me one unlicensed from America Sigma Pharm. The pharmacist told me yesterday this was because it was cheaper. The UK brand she told me would be £125 for 28 tablets as oppose to £125 for 90 of Sigma. I will see if she can get me this. I will look up the other results later as I am just going out but so thank you so much. 🙏
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
Adding T4 to T3 
T4 and T3
T3 instead of T4
T3 and muscle pain
T3 dosage
