I had my thriva results back. I was wondering about T3 - is it slower to respond than T4? If I am on the right dosage of levo will it catch up with the T4 since before levo it looked like my conversion was good!
In June, before levo, my results were: FT4 - 14 (12 - 22)- 23% through the range
: FT3 - 4.3 (3.1 - 6.8) - 32%
December, on 75mcg levo, my results are: FT4 - 17.1 (12 - 22) - 51%
: FT3 - 4.5 (3.1 0 6.8)- 37%
That conversion is worse! I'm not especially worried at this point because I know I still need an increase in Levo and my vitamins look like they're improving
about the conversion question..... the body always tries to maintain a stable level of T3 , and it has a system for doing this. When TSH rises this encourages a higher proportion of T3 to T4 to be released from the thyroid gland, and also encourages a higher rate of conversion from T4 to T3 within cells (i think)So your low t4 level before you took Levo would explain your apparently good conversion when you were not taking Levo. The system had turned up your T3 production and conversion to compensate for the low T4.
I think , because of this complex system, and the body's response to adding extra levo ,you probably can't directly compare conversion pre Levo to conversion when taking Levo.
You probably have to wait until you are on the best dose of Levo for you , before you can tell what your conversion is like when taking it.
Bear in mind that because of this complex system, you won't know what your conversion was like before you ended up with such a low level of T4, it may well have not looked so good in 'normal ' health for you.
I would add to tattybogle 's comments by saying that there's also that possibility that the actual thyroid was deliberately producing more T3 than T4 before you started the levo, to keep your FT3 levels up. It would do that because T3 is the active hormone, and therefore more important to the body than the the storage hormone, T4.
I think you're looking at it from the wrong angle. An appropriate dose of levo would be judged by the amount of T3 it converts to, not the other way round.
So if my body tries to maintain a certain level of T3 does that mean there comes a point where it realises there is 'enough' T4 to 'relax' a bit and start converting more of it to T3.
Sorry, I may be being a bit thick this afternoon - not feeling at my best - but it doesn't make much sense to me. I don't think conversion has anything to do with 'relaxing' - although I'm not really sure what you mean by that. But, no, I don't think that's how it works.
😂 despite an English degree I've never really mastered communication.
I guess I just feel like if my body has been furiously working trying to maintain my T3 levels because my T4 was low then at what point would it 'see' that there was plenty of T4 and stop trying to maintain but instead start improving.
Sorry - it's tricky trying to explain what I mean when I'm not even sure myself. 😂
I'm not sure that there's an answer to that question - at least, not one I know. However much T4 you have in your system, some of it will always be converted to T3. But, it isn't ever all converted to T3. Some of it will always be converted to rT3. But, obviously, the more T4 you have, the more T3 you will have.
No ,that would be too easy You can't assume anything with thyroid hormone dosing, results too often have a way of coming back 'opposite to expectations'
fT3 Level on a stable dose of Levo would be expected to stay the same.
If increase in Levo ,you might expect a slight increase in T3 , but not always.
Conversion can seem better when fT4 is a bit low, because higher TSH slightl increases t3 production from thyroid and conversion.
Conversion seems less good when there are higher levels of T4, since lower TSH slightly reduces T3 production and conversion.
It seems from many results on forum that T3 when on Levo gets up to a certain % for that person and then doesn't increase very much further however much more Levo they take.
I've written this a bit quick cos i've got to go ina minute , so it could be full of errors in logic .
Hopefully GG can come up with something more pithy and to the point
I thought that might be the case but I am ever the optimist. 😂
I am hopeful that 100mcg is enough (Going by the 1.6mcg by kg body weight equation I should be on around 92mcg) I do feel a huge improvement since diagnosis and I've improved vit D and working on the other 3.
So whatever your T3 level is, that's pretty much where it stays? In theory my T3 needs to be around 6 to be 'opitmal' but then that would mean I'd need T3? Because my T3 is around 4
Disclaimer: I do appreciate this is all theory and what makes you feel well is the right levels for you.
I think T3 probably would go up for most of us if we took much more levo then we are allowed nowadays due to the ruling God of TSH , but there are good reasons for not doing that, and it would be preferable to keep T4 in range and raise fT3 by adding some T3 (or use ndt instead)Before they could measure TSH accurately at low numbers, the doses of levo for some people were much higher than they are now, sometimes 300mcg daily . I've always wondered if, due to this ,there was less 'dissatisfaction with Levo' in the 60's than there is now that they can measure TSH better and are ruled by it rather than symptoms or fT4/3 levels.
But over range fT4 does come with increased risks for ... something .. i've forgotten.
There was a paper on here a while ago about it.
And also, over range fT4 will lead to more rT3 being made which also might not be great .but that gets a bit complicated.
But you're right .... this is all theoretical .... i understand a lot of the theory... but last blood test my TSH went up when it should have gone down , and my fT4 also went down when it should have gone up , despite me making certain the test conditions were consistent.
Sometimes i think the HPT axis is actually controlled by little blue pixies , having a laugh at us trying to do 'treatment by numbers'
Consider starting levothyroxine at a dosage of 1.6 micrograms per kilogram of body weight per day (rounded to the nearest 25 micrograms) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease.
Traditionally we have tended to start patients on a low dose of levothyroxine and titrate it up over a period of months.
RCT evidence suggests that for the majority of patients this is not necessary and may waste resources.
For patients aged >60y or with ischaemic heart disease, start levothyroxine at 25–50μg daily and titrate up every 3 to 6 weeks as tolerated.
For ALL other patients start at full replacement dose. For most this will equate to 1.6 μg/kg/day (approximately 100μg for a 60kg woman and 125μg for a 75kg man).
If you are starting treatment for subclinical hypothyroidism, this article advises starting at a dose close to the full treatment dose on the basis that it is difficult to assess symptom response unless a therapeutic dose has been trialled.
A small Dutch double-blind cross-over study (ArchIntMed 2010;170:1996) demonstrated that night time rather than morning dosing improved TSH suppression and free T4 measurements, but made no difference to subjective wellbeing. It is reasonable to take levothyroxine at night rather than in the morning, especially for individuals who do not eat late at night.
I think so! I thought I was 65kg but my scales say I'm 59kg so I've lost some weight. But 59kg works out at 94.4mcg so I'm optimistic 100mcg will be good for me. 🙂
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