T3 / T4 combination therapy dose advice?

[Stratocaster58]

Hi Everyone,

I've recently been prescribed T3 by an endocrinologist for the first time having been on T4 only for 20 years or so. I've been stable on a dose of 175 micro grams for a couple of years now (having had it reduced from 200), but haven't been feeling great - mental slowness / brain fog, extreme tiredness, and more recently very dry eyes and poor vision.

I recently paid for DNA testing (via ancestry) and found out that I have two faulty copies of the DIO1 gene, and one faulty copy of the DIO2 gene which would perhaps suggest a predisposition to conversion challenges?

I've noticed looking back over my historic blood tests over the last 20 years, where FT4 has been tested it is consistently above 20 and has been as high as 30. Where T3 has been tested (infrequently!) its typically in the range of 3.5-4.0

Could anyone give an opinion on whether or not my recent results (plus DNA results) suggest a conversion problem, and whether it is worth trying the combination therapy? Also it would be good to get some advice on the dose - the Endocrinologist has suggested reducing the T4 down to 125 mcg and adding 10 mcg of T3 (split into two does of 5 mcg). Does this sound sensible, I don't want to get even worse on this treatment, 125 mcg of levothyroxine seems very low!

I've attached my recent blood test results - its probably worth ignoring the most recent ferritin as I had just recovered from an e-coli water infection, so my inflammation markers were off the scale (CRP 55.1).

Another piece if information that came up in the DNA result, which I wonder if it could be relevant relates to how my body could have impaired ability to convert phenylalanine to tyrosine. Given tyrosines role as a building block of thyroid hormone, I wonder if this could be linked? Also it would perhaps seem relevant in terms of another common symptom of hypothyroidism that I have suffered from almost continually - depression. I appreciate that things that come up in DNA results do not mean that you'll 100% have or develop an issue, but as again I have two defective copies of this gene my chances of having an issue would be elevated. Not sure if this one has come up before?

Any advice much appreciated

[SeasideSusie Remembering]

Stratocaster58

I can't comment on your DNA results but your thyroid results alone are enough to tell us you don't convert well IF you followed the testing protocol advised here:

* Test no later than 9am

* Water only before test

* Last dose of Levo 24 hours before test to avoid false high or false low FT4 result

* No biotin/B Complex or any supplement containing biotin for 3-7 days before the test.

If you followed the above then your thyroid results are as accurate as can be and suggest that you may benefit from the addition of T3.

Your FT4 shows 81% through range and I think reducing Levo from175mcg to 125mcg is too much. At most a 25mcg reduction for a week or so before adding T3.

Then start adding T3 at 5mcg daily (you could try splitting dose into two if tablets allow). Wait 2 weeks to see if all OK and if so then increase to 10mcg daily, split into two if you wish. Wait 6-8 weeks then retest and see where levels are and how you feel. If necessary you then start tweaking, it's very individual where those of us on combination thyroid hormone replacement need our FT4 and FT3 levels and there is no one size fits all for dose, it's just a case of experimenting. I'm on combination replacement and at one time I was taking 31.25mcg T3 but the dose I've settled on is actually 18.75mcg.

Only change one thing at a time, if you change dose of Levo and T3 at the same time you wont know which one has made a difference.

When retesting remember the correct timing of last doses:

Levo - 24 hours

T3 - last part of a split dose the day before should be 8-12 hours before test.

[Stratocaster58 in reply to SeasideSusie]

thanks for your reply, yes I was meticulous in following the testing guidelines so I am confident the results are accurate. My gut feel was that a 50 mcg drop in my Levothyroxine was a bit too much. It would certainly complicate assessing the impact / results. It will be interesting to see if my T3 levels start to move in the right direction and crucially if I start to feel a bit better.

Also, the endo didn’t mention reducing the T4 dose before adding T3, but it obviously makes a lot of sense with the longer half life of T4.

Thanks for the information it’s much appreciated.

[SlowDragon Administrator]

Do you always get same brand levothyroxine at each prescription

Which brand?

Would agree, frequently dose levothyroxine is reduced far too much when T3 is added

Perhaps reduce to 150mcg daily

Wait a week after reducing dose levothyroxine before adding 5mcg T3 waking in morning

See how you get on

After a week or so, adding 2nd dose T3 mid-late afternoon

Retest thyroid levels in 6-8 weeks ….day before test delay 2nd dose T3 till approx 8-12 hours before test

[Stratocaster58 in reply to SlowDragon]

Many thanks for your reply.

I have been pretty consistent on Wockhardt 25’s and Accord 50/100 in terms of brand. I avoid the Teva 25’s and they resulted in things going even further out of whack.

150 mcg sounds sensible to me, as does leaving the week between scaling down T4 and adding T3.

Thanks again.