T4 T3 Results...Could anyone explain?

[SassyMH]

I had my bloods taken on 10th June and the readings were..... Free T4 18.5 (9-19)...Free T3 4 (2.6-5.7)...TSH <0.03 (0.35-4.94). I was taking 175mc Thyroxine 5 days and 150mc 2 days each week.

I started taking T3 as I have been feeling unwell for some time and getting muscle/joint problems, swollen hands and constant fatigue. I am also taking Vit D , Magnesium, Ferretin.

The NHS Endo told me how much to reduce my T4 by to add T3 (although he wont prescribe or fund it).

I had my bloods checked on 23July (again by GP who is being most supportive) and the readings are as follows.....Free T4 16 (9-19) Free T3 3.9 (2.6-5.7) TSH <0.03 (0.35-4.94).

I am taking 175mcg/150mcg on alternate days and 10mc T3 every day.

Both test were taken under identical conditions, no drugs 24 hours before, no food that morning prior to blood test. I am happy with my TSH, as I understand it that should remain supressed to keep thyroid cancer from returning; but I cant understand why T3 level has dropped (albeit marginally). I AM feeling better, my hands are not as swollen every morning, and my muscle and joint pain has gone despite doing more exercise (as I now have the energy to).

Question.....Should I up my T4 or T3 intake?

My GP is phoning on Monday so any advise before then would be very welcome.

Many Thanks

[Blueskyyy]

Hi

Just wondering why your dose is too high!

May I ask you what’s your actual weight as well as your height ?

[SeasideSusie Remembering]

SassyMH

no drugs 24 hours before,

Presumably you mean you didn't take your thyroid hormone replacement - Levo and T3 - 24 hours before.

When having thyroid tests, the time gap between last dose and blood draw, to give the normal circulating level of hormones, is

Levo - last dose 24 hours before

T3 - last dose 8-12 hours before

T3 has a short half life of approx 24 hours and starts to become undetectable in the blood after 12 hours. So you need to test within the recommended time frame. As T3 peaks in the blood 2-4 hours after ingestion you don't want to test too close to the blood draw as you get a false high, leaving longer than 12 hours and you get a false low.

If necessary we have to change the time of our doses the day before.

So looking at your two sets of results -

On Levo only:

Free T4 18.5 (9-19)

Free T3 4 (2.6-5.7)

TSH <0.03 (0.35-4.94)

On Levo plus T3:

Free T4 16 (9-19)

Free T3 3.9 (2.6-5.7)

TSH <0.03 (0.35-4.94)

Your FT4 has reduced with the reduction in your Levo which is to be expected. But because of the too long time gap between your last dose of T3 and blood draw you have a false low FT3 which is why it's showing lower than your previous test.

Do you take your Vit D, magnesium and iron tablets 4 hours away from your thyroid meds, and leave 2 hours between the iron and other supplements?

Also, are you taking Vit D's other important cofactor besides magnesium, which is Vit K2?

Question.....Should I up my T4 or T3 intake?

I don't think you should increase your Levo, and I wouldn't suggest altering your T3 dose until you've got results from a test done with the proper timing. There should be 6-8 weeks after any dose change before retesting which allows time for levels to settle.

[SassyMH in reply to SeasideSusie]

I had left 24 hours since T3 I will adjust that before my next test. Many thanks for your advice.

[Blueskyyy]

Well, I compared your two regimes, your initial LT-4 intake was 1175 mcg per week.

Under the new regime, your LT-4 intake is 1150 mcg per week, thus the reduction in FT4 level is expected.

T3 Dose should be splitted and taken in two small doses.

So it seems because you take only one dose and took your last 24 hours before blood test, your FT3 level reached its lowest point during the blood workup.

Take your T3 in two small doses (morning with LT-4 and at around 3 in the afternoon).

[SassyMH in reply to Blueskyyy]

Thank you. It seems I left too long gap between taking T3 and blood test. I will make sure I take T3 8 hours before next time. Does your weight affect the amount of T4/T3 taken. I am planning to loose the extra stone Im carrying once my drug levels are right. Thank you for your advice.

[greygoose in reply to SassyMH]

Not necessarily. You could lose weight and still need the same dose. You cannot predict your dose by your weight. You have to take what you need and never mind your weight, height or anything else.