Serum T3 too low? (Combo therapy): Hi, I have... - Thyroid UK

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Serum T3 too low? (Combo therapy)

cody_lamonica profile image
5 Replies

Hi, I have been stable on 150mcg T4 + 12.5mcg T3 for about 10 weeks (gradually dropped the levo and added the T3), I did this test the other week and was surprised to see such low serum T3.

- I did the test fasted at 9.20am

- The 12.5mcg T3 was taken the previous night at 9.20pm (12 hours before test - I was not splitting T3 dosages at the time, sometimes I do 6.25/6.25 but don't notice much difference)

I feel quite good mostly, far better than when I was on 175mcg or 200mcg T4 - more positive, less anxious etc. Probably not 100% though.

TSH is quite suppressed but FT3 is actually below range at the time of test.

- Note: I did the same test one week prior using exactly the same protocol (I had to retest as some results didn't come through), and the results were very similar, except the FT3 was 3.7 instead of 2.7

I am self medicating. Any advice? Should I just leave it where it is or is there room for improvement by adding more T3? Do my results appear undermedicated?

I would be grateful for any suggestions.

Thanks in advance.

TSH 0.29 mU/L (0.27 - 4.2)

FREE T3 2.7 pmol/L (3.1 - 6.8)

FREE THYROXINE 16.1 pmol/L (12 - 22)

VITAMIN D 109 nmol/L (50 - 175)

FOLATE - SERUM 9.55 ug/L (> 3.89)

VITAMIN B12 - ACTIVE >150 pmol/L (37.5 - 150)

FERRITIN 125 ug/L (30 - 400)

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DippyDame profile image
DippyDame

Your FT3 is below range so is under replaced.

I also self medicate (T3-only)...my journey is recorded in my bio. It may be of interest.

It looks as if your T4 to T3 conversion is poor resulting in low FT3 and your toleration of levothyroxine is poor given your trials with higher doses.

For good health almost every cell in the body must be flooded with T3 by way of a constant and adequate supply. The T3 must reach the nuclei of the cells where it becomes active and attaches to T3 receptors...then gets to work!

This sounds similar to my problem and it looks as if you need more T3 and less T4

Working that out may be a case of trial and error I'm afraid.

12.5mcg T3 is a relatively small dose in this situation so I'd start by adding another 6.25mcg for 2 weeks, see how that feels then add another 6.25mcg. Total 25mcg.

Wait for at least 6 weeks and test again with the usual test protocol.....at 9am, 24 hrs after last levo dose and 12 hours after T3 and at least an hour away from all food and drinks, except water.

For reliable results we need to be on a steady dose for at least 6 weeks before testing to allow the dose to settle into the system

You may need to reduce your levo dose at that stage...it's "wait and see"!

The T3 will naturally lower both TSH and FT4 so expect to see that reflected in new labs.

Your nutrients look ok.

Have you had thyroid antibodies TPO and Tg tested to check for thyroid autoimmune disease/ Hashimoto's....this can cause hormone levels to fluctuate.

Much depends on how we feel so I'd suggest you keep a record of that....I use an A5 diary to note all dose changes, symptoms etc.

Apologies if I'm telling you things you already know.

We're all here to help....just ask

Good luck!

cody_lamonica profile image
cody_lamonica in reply toDippyDame

Thanks for the reply.

FYI I have had RAI and whilst I was on T3 monotherapy previously I have undetectable T4 levels so it is fair to assume I have no thyroid.

I had RAI 8 years ago. I found my Graves relatively simple to manage for 15 years until I had RAI :(

Whilst planning this, my preferred option to aim for was actually 125 T4 / 25 T3, but after my ordeal with T3 mono (long story, it worked well but I got impatient then I couldn't sleep due to ridiculously high cortisol, I had to abandon it before I went insane), so I admit to being a little frightened of T3.

So, In the absence of any differing opinion, I will take your advice and increase to 150 / 18.75

I plan to split the T3 in 3 doses from now on. (6.25 TID)

I will evaluate symptoms and retest in the new year.

I appreciate your input to my situation.

DippyDame profile image
DippyDame in reply tocody_lamonica

Please read my reply again...I did not advise150mcg T4 + 18.5mcg T3.

That goes against everything I suggested!

I'd suggest you need to read more about T3 on this forum then perhaps that would reduce your fear.

T3 is no more dangerous than other medications if it is used correctly.

My comments were based on my own experience/ research and were suggestions rather than advice.

I realise you have had RAI and are consequently now permanently hypothyroid requiring life-long thyroid hormone replacement

Assuming that testing was done under correct protocol then above labs show...

FT4 is 41% through the ref range

FT3 is -10.81% ditto

Your FT3 is miserably low!

Both Frees should be roughly approaching 75% through their respective ref ranges, with the caveat that we are all different!

Because your FT3 is so low you will need to very, very slowly, and low, replace this to allow your body to adjust.... otherwise it will be like putting high octane racing fuel in an old Mini!!

Aiming to achieve a therapeutic dose of thyroid hormone is a very long, slow process and I'm afraid patience is vital. The body takes at least 6 weeks to adjust to a new dose. It could take a year or more to raise your suppressed FT3.

cody_lamonica profile image
cody_lamonica in reply toDippyDame

Thanks, I have re-read your post but remain confused, apologies if I am missing something.

I am on:

150 T4 / 12.5 T3

I thought you said add an extra 6.25 T3 each day for 2 weeks?

Isn't that:

150 T4 / 18.75 (total) T3 ?

DippyDame profile image
DippyDame in reply tocody_lamonica

Ah! You misunderstood my reply and you also multiplied wrongly.

I'll explain...

I didn't say...

add an extra 6.25 T3 each day for 2 weeks?

I absolutely didn't say "each day" that dosing would never happen

What I said was...

12.5mcg T3 is a relatively small dose in this situation so I'd start by adding another 6.25mcg for 2 weeks, see how that feels then add another 6.25mcg. Total 25mcg.

14 days of 6.25mcg T3 would be 14 x6.25 = 87.5mcg T3.

A huge difference to the 25mcg I pointed out in my reply

You wrongly calculated 14x6.25 as 18.75

Hope that's explained your confusion.

I'm wondering if you might be safer consulting an endo for face-to face-advice and monitoring, in order to avoid further confusion.

Take care.

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