Thyroid UK
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T4 to T3 conversion problem, calling Seaside Susie and friends for advice please!

Dear Forum Friends,

Can you advise if I should add T4 to my current regime?

I have DIO2 double mutation and was diagnosed hypothyroid last year,

I have been taking T3 25mcg daily and have now upped to 50 mcgs per day as symptoms not significantly improved. A different doctor from the one who originally prescribed T3 (but same surgery in Hong Kong) has looked at the results below (which were taken when on 25 mcgs T3 daily) and now prescribed T4 50 mcgs daily in addition to the agreed 50 mcgs T3 daily.

But surely with my conversion problem this is not a good idea to add T4! Please advise ... results he was looking at are below.

Many thanks for reading this post, best wishes to all, DP.

THYROID STIMULATING HORMONE 2.05 Range mIU/L 0.27 - 4.20

FREE THYROXINE *11.9 pmol/L 12.00 - 22.00

TOTAL THYROXINE(T4) 85.7 nmol/L 59.00 - 154.00

FREE T3 4.97 pmol/L 3.10 - 6.80

REVERSE T3 15

REVERSE T3 RATIO 21.57

THYROGLOBULIN ANTIBODY 10.500

THYROID PEROXIDASE ANTIBODIES 12.6

Interpretation of results:

HAEMATOLOGY

Vitamins

BIOCHEMISTRY

Inflammation Marker Iron Status

CRP - HIGH SENSITIVITY 0.88

FERRITIN 150

ACTIVE B12 *263.000 (25.10 - 165.00)

FOLATE (SERUM) 7.26 (2.91-50.00)

25 OH VITAMIN D 192 (50 - 200)

3 Replies
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Did you increase from 25 mcg to 50 in one go? That's really not a good idea. Increases for T3 should be 6.25 mcg every two weeks.

So, you were on T3 only, right? And your doctor wants to add in 50 mcg T4? That's probably because he saw your FT4 was under-range, and doesn't fully understand that that is normal when on T3 only. But, is it a good idea? Well, opinions vary. Some people think that you do need to have a little T4 in your system, even if you can't convert it. Others believe it's not necessary. But I don't think anyone has ever said it's a bad idea. I don't think it will do you any harm, and might do some good.

I was on T3 only for years. I had some very bad experiences on T4 only, and even worse on NDT, and had concluded that T4 just wasn't for me. However, recently, I got curious, and wondered what would happen if I added in a little T4. So, I started taking 25 mcg levo in February... Well, much to my relief, nothing bad has happened, and in some ways, I even feel better. My breathing has improved - I've had breathing problems all my life, but they'd been getting worse. Now they've improved. And, then someone told me that low T4 can cause breathing problems.

So, what I'd say is: try it and see. Maybe not the full 50 mcg. Maybe start with 25 mcg, and see how you go. :)

But, you do need to do something about your vit B12 and folate. They're very low.

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HI Greygoose,

Thanks so much for your reply, that's really useful. It's true that you should only increase doses very gently, but I was impatient and luckily even 50 mcgs doesn't feel like it's having a big effect. My worry with adding T4 was that the doctor hadn't bothered to look in my notes and see the conversion issue. It's all about finding the right combo for each individual and hearing your experience is very helpful ...

My B12 is actually over the limit so the doctor said to stop B12 supplement. The Hong Kong surgery asked me to do the '23 and me' genetic test which when analysed identified MTHFR mutation that apparently means that I need to take a different form of Vit B and avoid folic acid ... so I'm rethinking my supplements at the mo.

It's a complex landscape isn't it? So pleased to hear that your breathing has improved with the addition of T 4. I'll report back if I have a benefit from, adding some myself!

Very best wishes DP

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It probably wouldn't have made any difference if he had looked at your notes - although very bad of him not to have! Because they don't understand about this gene, and what it means. :(

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