Free t4 question

Hi everyone,

I was last year on levo, my free t4 was 15 10-24

Now on t3 only

Free t4 now 3

still waiting for a understanding on trh test not tsh.. Saw my endo today and he does not think I've got under active thyroid, but yet if I stop the t3, like he asked me, my symptoms returned, I'm awaiting results without t3 in my system.

I asked if I wasn't taking levo and I have under active thyroid, wouldn't my ft4 be low? I also asked if I was a healthy thyroid patient and taking levo wouldn't my ft4 be on the higher if not over range?

He said, no the reason your ft4 is low is because the t3 is suppressing your ft4 and he said, if someone with a healthy thyroid and taking 150mcg of levo like I was, wouldn't have a high ft4..

My tsh at the time was 1.13 on levo, ft4 15 as above.

Now on t3

Last test was

Tsh 2.53. 0.27-4.2

Ft4 3. 10-24

Ft3 3.9 2.8- 7.1

Can some one explain ft4 results on someone on levo, a healthy patient and a patient on t3 only

Many thanks for reading.

10 Replies

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  • Nikki356, FT4 is low because you are taking T3 only. A euthyroid patient would be expected to have TSH 0.5-1.7, FT4 mid-upper range and FT3 mid-upper range. A patient optimally medicated on Levothyroxine will be expected to have TSH around 1.0, FT4 in the upper range, and FT3 mid to upper third of range.

    I think your last test indicates you were undermedicated. A patient optimally medicated on T3 only will usually have TSH <0.1, low FT4, and FT3 in the upper third of range ie >5.6.

    _______________________________________________________________________________

    I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

  • Nikki,

    TRH is thyrotropin-releasing hormone produced by the hypothalamus, that stimulates the release of TSH (thyroid-stimulating hormone) and prolactin from the anterior pituitary.

    Re test results: It is difficult to answer as there are so many different scenarios depending on why the thyroid isn't secreting (enough) hormone, other health issues & how much T4 (&T3) is being medicated, etc but generally a good result would be TSH of 1.0 or below, T4 & T3 in top third of upper range.

    It is thought that T4 will more readily convert to T3 with the addition of extra T3 promoting cell uptake and only a measured amount of RT3 being produced. Therefore the T3 result may be expected to be a little higher.

    I don't know a lot about medicating T3 only but understand that the TSH and T4 results aren't so important. The T3 result should be high enough to feel well but not over range.

    If you had a TSH of 1.13, FT4 of 15 last year when medicating 150mcg Levo, you must need thyroid hormone replacement. Otherwise you would feel overmedicated.

    How do you feel now on T3 alone ?

    Flower

    ……………………………………………………………………………………………………………………

    Disclaimer: I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

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  • I feel fine... I have to adjust according to how I feel... But generally well, I notice when I drop it to low I feel awful (hypo)

    Flower.. Do you know much about trh result interpretation?

    The endo said, that the t3 wouldn't of made no difference to the result and therefore I'm not hypothyroid.. I'm sure he has this wrong.

  • No I don't know much about TRH results Nikki.

    One scenario I have read about may be that when results show a low T4, T3 and TSH it can be suggested that the hypothalamus is not activated by low thyroid hormone so TRH is poorly produced (in response to hypothalamus) and pituitary may not respond so TSH always remains low. However your T4 goes up and down so is responding to thyroid hormone replacement.

    Of course T3 will make a difference to the result. It is the active hormone and if you didn't need it I think you would have an over range result and feel very over medicated (hot, palpitations, anxiety, etc).

    I agree with Clutter and say you are slightly undermedicated still but if you feel fine ... great.

    Flower.

  • Friday I will have new results, I shall post them when I get them, not feeling great right now, feeling hypo most days, but when I take half of a half, I feel fine for a bit then back to hypo feeling,

    Im wondering if my endo is trying to get out of prescribing t3...

  • What dose T3 are you medicating and have you tried splitting the dose?

    F

  • I was taking them all at once 50mcg... Early December I started feeling like over active, reduced it down to 1 and half...

    Now I take 25 in the morning and around 2pm half of 25 or half of a half, ( sorry brain isn't feeling mathematical tonight.)Depending on how I feel.

    My temp never goes over 36.5 my blood pressure is always brilliant, heart rate 60-80 .

    I'm not one for checking everyday, but when I felt over active, my temp raised to 36.7 not a great deal. anxious, lack

    Of sleep.

    I'd check my temp in the morning and it would be as low as 35...

    My nails have broken below comfortable level, hair, skin dry brittle, all the usual symptoms of hypothyroidism, I'm

    Wondering whether to add in a little t4 but now my endo doesn't believe I have a under active thyroid, he won't prescribe that either.

    I am seeing him again to discuss new bloods though.

  • Sorry to hear you feel so unwell.

    Have you considered cortisol levels and good gut health? Both can inhibit thyroid hormone function if impaired.

    Flower

    Thyroid & Cortisol connection

    hypothyroidmom.com/cortisol...

    Thyroid & Gut connection

    chriskresser.com/the-thyroi...

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    Disclaimer: I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

    ………………………………………………………………………………

  • Thank you for the links, I have considered them, I think I will invest in a saliva test, show my endo as well, as I know he is aware of adrenal fatigue.

  • My endo has offered to refer me to any endo in the country.. If I find one, I know my endo, he has been very supportive, and does admit he is a very traditional t4 endo specialist. And t3 is very new to him. I will take him up on his offer..

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