Hello, I know I've probably been told this before but I can't remember - sorry. When taking T3 and T4 should Endo be determining doses by looking at TSH? Is it ever dangerous if TSH is undetectable ie <0.02
As usual looking forward to your helpful answers
Doctors should never be dosing by the TSH, no matter what you're taking. The most important number is the FT3 - especially when you're taking T3. If you're on T4 monotherapy, then he should also take the FT4 into consideration. Once the TSH is below 1, it doesn't give much relevent information.
No, it is in no way dangerous to have an undetectable TSH. That just means that the pituitary has decided there's enough thyroid hormone in the blood, so you don't need TSH anymore. 
Thanks grey gooseWhy then do endocrinologists (including Dr Toft) say TSH should be between a particular reference range (can't exactly remember what numbers are here)
Not sure if you can find my last post but I'm still having cognitive difficulties taking 75mcg T4 and 40mcg T3 (20mcg am and 20mcg pm) my FT4 is below reference range at 10.3 and FT3 5 (hoping you can see my old post with reference ranges). Do you know if generally people need both T4 and T3 to be in the reference range (my Endo doesn't seem to know this) btw I have the homozygous polymorphism of the DIO2 gene.
Sorry for long post but I'm desperate to feel well again and just wish Endo would reassure me he knew what he was doing - unless it is just trial and error
Well, it is just trial and error, but even so, I doubt your endo has much idea what he's doing. Not many of them do. They're mostly diabetes specialist.
Why do doctors say the TSH should be in-range? Because that's what they were told in med school. And they never question what they were told in med school - it's sacred! And, because they have very little idea how these things work. If this subject interests you, have a look at this thread:
healthunlocked.com/thyroidu...
Thanks for replies grey goose and lalatoot So do you think my cognitive issues could be related to the fact that my FT4 is below reference range and FT3 at 5
Do you know if people generally do better when both FT4 and FT3 are within reference range?
Your cognitive issues could very well be due to being hypo, yes. Whether or not it's due to the below reference range T4 or the low T3 is anybody's guess. Thyroid is very personel. No one-size solution fits everybody. Myself, I'm at my best when my FT4 is zero and my FT3 is top of the range. But, different people need different levels, and a lot of people would need their FT4 a lot higher than yours. But, as said before, it's all trial and error. Maybe you need your FT4 higher, maybe you need your FT3 higher, maybe both. You just have to try different doses until you find the one that is a perfect fit for you: your sweet-spot!
Thanks for your reply greygoose.
I have so many questions I am hoping you kind people can help me with and I've numbered them for ease:
1. So when I was on 125mcg T4 and 20mcg T3 (FT4 23 & FT3 6) and still not right should I be aiming for higher than 6 on FT3 reference range since FT4 is so near top of range? I am thinking at this point it would have been better for Endo to keep T4 at 125mcg and increase T3 to 30mcg. He didn't do this, instead he reduced T4 to 75mcg and increased T3 to 30mcg.
2. Does increasing T3 meds have an affect on FT4? I am asking this as I'm wondering why Endo reduced T4 meds when he increased T3.
3. Now my blood test results are 10.3 FT4 (taking 75mcg T4) and 5 FT3 (taking 30mcg T3) (Endo has just increased T3 to 40mcg - he wanted to reduce T4 too but I pushed to just change one thing at a time) what dosage change can anyone suggest and any explanation would be appreciated as I try very hard to navigate this condition
4. Endo always wants to change both T4 and T3 dose at the same time. Increasing T3 and reducing T4 - what can I say to him to get him to stop doing this
4. If my Endo won't agree to changes I will reluctantly have to self medicate (something I'm nervous about doing) so can you buy both T4 and T3 from somewhere (where?) and is it safe
4. As I'm completely fed up (to say the least) about feeling so unwell and not fully engaging in life I was again reluctantly thinking about whether other medication would help get me over this hurdle eg antidepressants or anti anxiety meds - any thoughts
I am so so sorry for this long post and thank you all, as always, for your continued help
I suspect a big part of the problem is this endo is making rather heavy handed changes. and like you say .. changing two things at once is rarely a good idea (and possibly too frequently, but i haven't read your previous , so don't know when these dose changes have been made)
eg when fT4 was 23 (presumably over range?) a slight reduction in T4 was probably wise .. and see how that went for a while before then perhaps considering increasing T3 slightly once they saw the bloods from a bit less Levo... but chopping Levo dose nearly in half to 75? and increasing T3 quite a lot to 30 at the same time.. seems to be asking for trouble to me...... and now of course fT4 has dropped massively.
Ask him to look up the word 'subtle'
Really not sure what he was thinking , suggesting you reduce Levo further when fT4 was only 10.3.... that seems a bit daft too .
And increasing T3 in such big lumps as 10mcg at a time ... not sure that's very wise either .. he he never heard of 5mcg /quarter of a tablet?
Have you considered nodding politely in order to get his prescription to source the meds but then ignoring his dose suggestions and using your own judgement to make rather more subtle adjustments ? he won't know what you actually took unless you choose to tell him.
Thanks tattybogle, that's a good ideaSo if I'm now taking 75mcg T4 and FT4 is 10.3 and 40mcg T3 - FT3 5 - what do you think I should tweak?
Hi , i've just read through your previous posts trying to sort out your history :The word 'disorganised' comes to mind
We need to know in chronological order ~dose changes /date / test results (after ? how long) on that dose. It would be a very good idea to write a new post showing with a clear and accurate history .
(eg. some replies to your previous posts are based on you giving blood results that were not from the dose you were taking at the time you were asking the questions , we don't know if any these tests were done properly eg. one of them seems to be from only 2 /3 weeks after a dose change, and it' s not at all clear what doses you were taking to get the few blood results we do have)
So far i've got this:
hypo since 2016
April 2020 when felt well :
TSH 1.17 fT4 10.7 fT3 4.7 (i cant see what you were taking)
23rd Sept 2021:
TSH 0.07 fT4 14.8 [10.8 -25.5] fT3 4.5 ( ? 75 Levo /5 mcg T3, or ?100 Levo /5 T3 ?)
25th Sept : Increased to 125 Levo/10 T3
9th Oct this increase led to shortness of breath, occasional headache, and being aware of heartbeat.
13th Oct : ( only 2 /3 weeks on new dose ? far too soon to test):
TSH <0.02 fT4 22.4[10.8 -25.5] fT3 5.7 [3.1-6.8]
You said Endo suggested increasing Levo to 150mcg / and reducing T3 to 5mcg ? but in a later post you replied to Slow dragon saying you'd tried 100mcg Levo /20mcg T3 .
Then in this post you say :I was on 125mcg T4 and 20mcg T3 (FT4 23 & FT3 6)
Now you're on 75mcg Levo /30mcg T3 and say you are feeling improved:
TSH <0.02 fT4 fT4 10.3[10.8 -25.5] fT3 5 3.1-6.8]
How long had you been on this dose before you took this blood test ?
I suggest you stay on the same dose for now and see if these improvements continue, You seem to have had A LOT of changes since October , but the body likes stability, if it gets it then it will often continue to improve over quite a few months.
Since you are already feel improved on 75Levo /30 T3 that is a sign that something is right for you .. i suggest you don't mess that up by changing anything else at the moment ....
and in the meantime .. write a new post clearly showing you r history of what you've taken/ for how long /and what the blood results were.
(p.s It is interesting to note that your current fT4 /fT3 levels are very similar to what they were in April 2020 when you said you felt well ..another reason to leave things alone for a while)
Yes I agree tattybogle and thanks so much for wading through my history - I really appreciate the effort and time you have taken 🙏
1. So when I was on 125mcg T4 and 20mcg T3 (FT4 23 & FT3 6) and still not right should I be aiming for higher than 6 on FT3 reference range since FT4 is so near top of range? I am thinking at this point it would have been better for Endo to keep T4 at 125mcg and increase T3 to 30mcg. He didn't do this, instead he reduced T4 to 75mcg and increased T3 to 30mcg.
Impossible to say what he should have done, but decreasing by 50 mcg levo and increasing by 10 mcg T3 all in one go was very, very wrong. Your poor body won't have known what hit it! Not surprising it didn't make you better. One should only increase/decrease levo by maximum 25 mcg every six weeks, and T3 by maxim 5 mcg every two weeks, or it's rather like hitting the system with a sledge hammer.
Finding the right dose is always a matter of trial and error, and has to be done very slowly, giving your body time to adjust.
2. Does increasing T3 meds have an affect on FT4? I am asking this as I'm wondering why Endo reduced T4 meds when he increased T3.
Yes, it lowers the FT4 level. And, frankly, it's not always necessary to reduce the dose. But, that's what doctors were told to do in med school, so that's what they blindly do, not thinking about the consequences or the reasoning behind it. Robots!
3. Now my blood test results are 10.3 FT4 (taking 75mcg T4) and 5 FT3 (taking 30mcg T3) (Endo has just increased T3 to 40mcg - he wanted to reduce T4 too but I pushed to just change one thing at a time) what dosage change can anyone suggest and any explanation would be appreciated as I try very hard to navigate this condition
Your endo wants shooting!!! He's going to kill you like that. You can't keep increasing T3 like that, you're going to shoot straight past your sweet-spot and never notice it.
The whole idea behind thyroid hormone replacement is to start low, and increase slowly until you feel well. But, over-shoot that sweet-spot and you're never going to feel well because being over-medicated is as bad as being under-medicated.
How much levo were you taking when you started taking T3? What level was your FT4, do you know? And, how much T3 did he start you on?
4. If my Endo won't agree to changes I will reluctantly have to self medicate (something I'm nervous about doing) so can you buy both T4 and T3 from somewhere (where?) and is it safe
Your endo doesn't have to agree to changes. As long as you're getting your prescription for T4 and T3 every month, you can do what you like with it. And, 40 mcg T3 is quite a generous prescription! So, don't rock the boat!
No need to feel nervous, we're all here to help you, and so many of us do it, these days, there's a wealth of knowledge to tap into. Yes, you can buy both T4 and T3 on-line. And, yes it is safe if you buy from recommended sources. To get hold of those sources, write a new post asking for PMs giving people's trusted sources. But, if you can hang on to your prescription, I would, if I were you.
4. As I'm completely fed up (to say the least) about feeling so unwell and not fully engaging in life I was again reluctantly thinking about whether other medication would help get me over this hurdle eg antidepressants or anti anxiety meds - any thoughts
Yes. Don't. You're not suffering from antidepressant deficiency. You're suffering from thyroid hormone deficiency, and possibly some nutritional deficiencies as a result, which has completely upset your balance. And, only restoring what's missing can set you right again. Antidepressants and anti-anxiety meds mess with your brain. And, I'm very anti-antidepressants. What's more, they're addictive and hard to come off once you think you no-longer need them. Best never to start. Bit like excessuve smoking or drinking alcohol.
Have you had your nutrients tested: vit D, vit B12, folate, ferritin? Most nutrients, like most hormones, can cause depression when in deficit. We need to get everything optimal.
I can't thank you enough greygoose for your thorough response - I honestly cannot thank you enough.
I will post tomorrow with details you ask and perhaps you or anyone can advise where on earth I go now with dosing
Honestly thanks so much for all your help 🙂
You're very welcome.
But I would suggest that you start a new thread with your details, linking to this one. That way, more people who might be able to help will see it.
Thanks for the tip but here comes a technical question - how on earth do I link to this post 😊
On a computer (rather than phone), it is usually easy to copy the address from the address bar. Then paste it into another post.
Sorry but I have a supplementary question - so does it make a difference when looking at FT3 reference range if the result is coming directly from T3 meds or being converted from T4
Thanks 🙏
I'm honestly not sure about that one. I think I've read somewhere that it does, but elsewhere I've read that it doesn't. helvella , what's your take on that? Does it make any difference?
FT3 supplied by a working thyroid will result in a more even level in the bloodstream.
Taken as tablets, it will tend to appear more like a sawtooth shape - rising sharply after taking a dose, and falling until the next dose.
Therefore, the time of the blood draw is far more important when you are taking T3.
greygoose
Also, the FT3 is likely to be lower in-range when dependant entirely on conversion, than it would be if taking T3 directly in a pill.
If on T4 monotherapy, and dependant on conversion, the FT4 will usually be higher than within the range than the FT3. Taking T3 directly will lower the FT4 level, so the FT3 will tend to be higher in-range than the FT4.
Are you asking because you're planning to buy your own T3 and don't want your doctor to realise what you're doing? If so, I very much doubt he would understand the significance of the different levels. They aren't very good at interpreting blood test results.
At the top right hand corner of this screen there is an icon - More :
Press here and choose to go to your profile where you should be able to see all your previous posts :
My cognitive function was severely compromised on T4 monotherapy and once I started taking a little T3 alongside my T4 it was like a light being switched on in my brain.
Thanks for your reply pennyannie. May I please ask whether you have the faulty DIO2 gene and also, just out of interest what doses you take and what your blood test results are.
Also, I don't seem to have the same functionality ie my More icon doesn't lead me to see previous posts. Could this have anything to do with the fact that I'm using smartphone (android)
Golly - I'm not up with ' tech ' and don't even possess a smart phone :
I'm totally the wrong one to ask about any of this :
I do not have the D102 - I don't even have a thyroid - try pressing on the icon alongside my name here and this should lead you to my profile page.
Once on any form of thyroid hormone replacement is is essential that you are dosed and monitored on your T3 and T4 blood test results :
The TSH was originally introduced as a diagnostic tool to help confirm a case of hypothyroidism and was never intended to be used once the patient was on any form of thyroid hormone replacement.
I am much improved now thanks in the most part to this forum and I am self medicating and my TSH is at 0.01.
P.S.
Does the icon send you to a different page on which it then says " view profile " that is of course if you wrote one I suppose ??
At the top right, click on the icon + More.
Then choose Update profile.
And, when you get there, at the top it says View my profile.
Then you can see your posts!
Silly that it takes so many steps.
Thanks helvella - I can see them now 😊
Handsome14
Why then do endocrinologists (including Dr Toft) say TSH should be between a particular reference range (can't exactly remember what numbers are here)
Actually, Dr Toft said this in Pulse Magazine (the professional publication for doctors):
"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l. In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l. Most patients will feel well in that circumstance. But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l. This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l).*"
*He confirmed, during a talk he gave to The Thyroid Trust, that this applies to Free T3 as well as Total T3 and this is when on Levo only. You can hear this at 1 hour 19 mins to 1 hour 21 minutes in this video of that talk youtu.be/HYhYAVyKzhw
If you wish you can obtain a copy of the article by emailing ThyroidUK at
tukadmin@thyroiduk.org
It's in answer to question 6.
Is it ever dangerous if TSH is undetectable ie <0.02
Depending on how low the machine tests (and they are all calibrated differently) my TSH comes back as <0.005 or <0.01 or <0.02 and I haven't yet spontaneously combusted, exploded or popped my clogs 😊
Thanks for reply SeasideSusie. So does what Dr Toft says not apply when on both T4 and T3
No, it doesn't, it's when on Levo only. Sorry, I've just looked back at your opening post and see that you mention that you take Levo plus T3 and I missed that, my apologies. However, what I said about my own level still applies as I take Levo plus T3 (T3 is self sourced and GP thinks I take Levo only). GP doesn't like my suppressed TSH but I have NHS records going back over 20 years showing that on Levo only my TSH was 0.02 and 0.03 so I have a long history of suppressed TSH. It doesn't worry me but it's something you have to make your own mind up about
Super thanks SeasideSusie 🙏
My TSH has been undetectable for a long time. I have acknowledged this formally with the drs., listened to their warnings of atrial fibrillation and osteoporosis and got them to note and to accept that I take all responsibility for keeping my TSH suppressed. Now we have got that out of the way it is no longer an issue with them.I must also point out that my FT4 and Ft3 are both well within range so I can dispute any notion of overmedication.
I used to repsect a dr's. knowledge but I no longer do having been woefully treated for years. It pays to know as much as you can about thyroid and to be pushy.
I don't know if there is a should with thyroid medication but my endocrinologist goes by my symptoms and not test results. I am aware though that there is probably a risk since I get palpitations when on enough T3 to feel okay and have osteopoenia. I think it's an individual choice, I'll take that risk to have a better quality of life where many others would rather have low energy and anticipate a longer life. Don't think I've answered your question helpfully but I did set out to!
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