Body basal temp and combi therapy (T4+T3) - Thyroid UK

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Body basal temp and combi therapy (T4+T3)

Blueskyyy profile image
14 Replies

Hi

This is my first post, I am struggling to normalize my tsh, levothyroxin didn’t normalize TSH even with 112.5 mcg per day, Doctor decided to switch to combi ( 125 mcg T4 + 12.5 mcg T3 ).

I started the combi therapy on 14.07, I track my body basal every day in the morning, I noticed that my temp decreased.

Under only T4 therapy, my temp was between 36.25 and 36.50, it decreased to 36.00 -36.25 under combined therapy.

I have attached the bbt chart .

What can I conclude from this issue ?

Thx

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Blueskyyy
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SlowDragon profile image
SlowDragonAdministrator

Do you have Hashimoto's? If so levels fluctuate

Menstrual cycle can alter temp too

Bloods should be retested 6-8 weeks after each dose change in Levothyroxine or T3

Or brand of Levothyroxine or brand of T3

Because taking any T3 reduces TSH right down, you may have switched your own thyroid output down to zero, and now need small dose increase in Levothyroxine or T3

Many people find T3 needs to be split dose 2 or 3 times per 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

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

Blueskyyy profile image
Blueskyyy in reply toSlowDragon

Thank you !

Yes I have hashimoto, what you mean exactly with “Because taking any T3 reduces TSH right down, you may have switched your own thyroid output down to zero, and now need small dose increase in Levothyroxine or T3” ?

I didn’t reduce levothyroxin dose, instead I increased it because with 112.5 T4 (only T4 therapy ) my TSH was 8!

Doctor said I have two options : either I take 150 T4 or 125 T4 + 12.5 T3 ..

I tried 150 mcg T4 for one day and i felt very bad, then I stared the combi therapy.

The one thing that I don’t understand, if the combi therapy was able to increase FT4, FT3 and reduced TSH, the temperature must increase not decrease !

Correct ?

SlowDragon profile image
SlowDragonAdministrator in reply toBlueskyyy

Yes.....and no

Taking any dose of T3 almost always reduces TSH right down often well under 1

If when your TSH was 8, your own thyroud was still producing equivalent of about 75mcg Levothyroxine.....

when adding 12.5mcg T3 (roughly equivalent to 25mcg -50mcg Levothyroxine) then you have had an overall dose decrease because your own thyroid output has stopped ....because TSH dropping

One of the reasons endocrinologists don't like T3....is because the TSH is almost always suppressed

So you have to ignore TSH and always test FT3 and FT4

TSH has dropped...but FT3 and FT4 may still be too low

Blueskyyy profile image
Blueskyyy in reply toSlowDragon

I think my case is a bit complex.

First of all, my weight is only 61 kg.

For a person with 1.67 m2 body mass index like me, the thyroid produces physiologically 93 mcg T4 + 27 mcg T3 (20% directly ~ 6 mcg + 80% from T4-T3 conversion )

Based on the calculated physiological hormones production, I can say that I am already supplementing my body far more than what it ever produced originally under healthy conditions.

In addition to that, my FT4 Level under 112.5 mcg T4 ( during LT-4 therapy ) was 18 pmol/l (range 12.1-20.1) ... however I took levothryxoin 4 hours before blood test !

Doctor told me that LT-4 therapy sometimes fails to normalize TSH despite Normal hormones level, so there is need to add a bit T3.

In fact, we added T3 only to inhibit TSH.

So back to your analysis, how do you know that my natural T4 production is now reduced by 75 mcg, if I had initially FT4 of 18 under 112.5 mcg T4 ?

Judithdalston profile image
Judithdalston in reply toBlueskyyy

We are all complex, and once we have thyroid conditions most of the active members of this forum find that we seem to need more hormones that such calculations suggest. Once you add T3 it becomes even more complicated...TSH becomes very low or suppressed, and FT4 goes down. I was on 75 mcg of T3 and never got my basal temperature over 36.2C; I would not rely on anything less than 6 weeks to judge how you feel, your metabolism, or how your bloods might be, whether changing levo. or T3 dosing. Be patient.

Blueskyyy profile image
Blueskyyy in reply toJudithdalston

Thank you very much !

You’re right, I must wait 6 weeks before I judge, I feel relatively better with T4+T3.

I added T3 because TSH didn’t normalize with T4.

Previous therapy consisted of 112.5 T4 which resulted in FT4 in upper half, FT3 in middle of range while TSH was 8.

New therapy consists of 125 T4 + 12.5 T3 (taken in two small doses).

I hope that TsH get suppressed, FT3 increases a Bit and FT4 in upper Quadrant of the Range.

So, what could be the cause of your low temp ? you say that you have suppressed TSh and normal FT4 , Ft3!

Judithdalston profile image
Judithdalston in reply toBlueskyyy

Some research suggests that once you have had low basal temp., and suppressed TSH ( not necessarily related) for a long time you don’t necessarily get them back again when for eg lowering T3 dosing, or other thyroid adjustments. My FT4 was also negligible on last test, but infact since not felt any better of high T3 only dose ( and got greatly raised blood sugars) now reversed to lower T3 and reintroduce Levo. I might try the 3/4 thru range of both FT4 and FT3, which might need more levo., less T3. I keep a diary of how I feel, symptoms, basal temp, bp,pulse, blood sugars, weight etc, and dosing including supplements/results , but you could add such things to your computer generated chart too...worth while to look back on what worked or not etc.

SlowDragon profile image
SlowDragonAdministrator in reply toBlueskyyy

Many of us when hypothyroid, especially if Hashimoto's, have malabsorption issues and/or gluten intolerance and/or lactose intolerance

All of these can mean you need higher dose that you might expect

Vitamin levels need to be optimal too. Not just somewhere within range

It's an extremely complex disease. Most endocrinologists never consider the gut aspect (not their field of expertise)

Genetic issues only just starting to be considered

Relatively common to have DIO2 gene variation

This can mean benefit from addition of T3 alongside Levothyroxine

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

Other genetic issues can be relevant too

bluehorizonbloodtests.co.uk...

MTHFR pretty common as well

Each time dose or brand of Levothyroxine or T3.is changed important to get bloods retested 6-8 weeks later

Testing as early as possible in morning and fasting

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

And 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

Blueskyyy profile image
Blueskyyy in reply toSlowDragon

I understand what you want to say, however I am trying to understand why T3 reduced my temp instead of increasing it.

I am sure my FT4 didn’t decrease, since I am supplying my body with 125 T4 + 12.5 T3. The only possible change could be a lowered /suppressed TSH.

SlowDragon profile image
SlowDragonAdministrator in reply toBlueskyyy

Suppressed TSH is highly likely...almost inevitable

After all our thyroid only produces tiny doses of T3 slowly across a whole 24 hours straight into blood stream.

Whereas synthetic replacement, even at 6.25mcg dose is a large amount in the gut and pituitary is extremely sensitive to T3 .......even if FT4 and FT3 are actually too low

We often see patients on Levo plus T3 who have suppressed TSH and relatively low FT3 and FT4.

Come back with new post once you get results and ranges, making sure to leave correct time gaps before testing

SilverAvocado profile image
SilverAvocado

Blueskyyy, why are you trying to normalise your TSH? I'd say a more reasonable goal would be to reduce symptoms and get yourself well. If you want to reduce this into blood tests terms, the most reasonable thyroid blood test to use would be freeT3, as this is the test that most closely reflects symptoms. I would suggest aiming to get your freeT3 into the top third of the range.

It sounds like someone has told you that 112.5mcg of T4 is a high dose? Actually it's not particularly high, and everyone is different. Some people need higher doses to get their blood tests looking good, or higher doses to reduce symptoms. Personally I have some kind of thyroid hormone resistance, which means I need a very high dose. You can't really predict what your hormone needs will be, all you can do is try out every possibility and figure it out empirically from your own results.

You've only got a week or so of data on your new dose. In my experience after a dose increase pulse and temperature measures will become very erratic for several weeks. I can get almost any kind of symptom during this time, feeling undermedicated, overmedicated, new symptoms emerging or existing symptoms getting better or worse, etc, etc. It's only around week 4 when things start to settle down for me. My suggestion would be to wait out 6-8 weeks, and don't start being concerned until you get to that point.

The dose increase you've had is rather large. T3 is 3-5 times more potent then T4, so the increase you've had is 12.5mcg of T4 + 12.5mcg of T3 which is equivalent to about 50mcg of T4, giving a total increase of the equivalent of 62.5mcg of T4! This is an increase of more than 50% of your previous dose, it would have been more cautious to do this in two or three separate increases over a 12-18 week period.

This big increase is probably part of the reason you've had surprising results. You've given your body a bit of a shock, and it is having a period of upheaval changing things around to accommodate the new dose. Some people can struggle to introduce T3 so it is best to start out very slowly. Usually these people will feel like they're overmedicated even though they clearly aren't, e.g. Feeling too hot restless, pumping heart, anxious, etc, so quite different from what you've felt. But anything is possible.

Blueskyyy profile image
Blueskyyy in reply toSilverAvocado

Ty,

Basically I want to reduce TSH because I read its causes problems in pregnancy.

My symptoms have improved dramatically after taking 12.5 T3.

I discussed the dose increase with my doctor and agreed that we need to top up the dose as my TSH was consistently high, one day it reached 64 ! I was then on 75 mcg T4.

TSH was 13 when I was on 100 mcg T4, then it decreased to 8,7 when I started taking 112.5 mcg T4.

My FT4 was in the upper half of the range while FT4 was at around 32%.

Adding T3 was a good decision and i was the one who suggested that, my doctor wanted that I take 150 mcg T4 but I refused!

SilverAvocado profile image
SilverAvocado in reply toBlueskyyy

Unfortunately doctors will often spout a lot of nonsense! It's good you were able to persuade yours to prescribe T3.

Although guidelines will often mention TSH needed for a successful pregnancy, this will be because they are using TSH as the sole measure of our thyroid status. Doctors often use TSH only, and don't use the full thyroid panel of three blood tests, which is much more informative.

But TSH is a very inadequate measure, it's possible to have a nice looking TSH, but still be quite ill. Symptoms are the most important thing to judge by, including temperature and pulse as you have been doing, after symptoms the best blood test to go by is freeT3. T3 is the active hormone needed by every cell in the body, this test tells you how much is available in the blood.

Blueskyyy profile image
Blueskyyy in reply toSilverAvocado

... besides to that, TSH can pass the placenta, so it’s very important to have a normal TSH

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