which labs to pay most attention to when on NDT... - Thyroid UK

Thyroid UK

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which labs to pay most attention to when on NDT...?

I have been on Thyroid-S from Thailand for about two years now. Feeling good most of the time, and I have managed to lose all the weight I put on while being hypothyroid and on T4 only drugs (in total 20 kilograms or 3 stones). However, both my FTs are pretty lowish:

FT4 0.8 ng/dL (ref 0.7-1.5)

FT3 2.9 pg/mL (ref 1.7-3.7)

I take NDT once daily, in the morning, and go to the lab 24 hours after taking any. So my FT3 levels were probably a little higher (+/-20% higher?) the previous day.

My doctor, who was trained by Thierry Hertoghe, said my FTs don't matter that much since my TSH is completely suppressed (<0.01), which means the NDT is working (my doctor thinks I'm on Erfa, BTW).

This is a new way of looking at things...normally, when on NDT, you look at your FTs, especially your FT3 levels, to decide whether you are under-, over- or optimally medicated. My doctor chooses to see my suppressed TSH as a sign of being optimally medicated.

I have previously tried to raise the Thyroid-S but ended up with hyper symptoms within days, so the dose I am currently taking (and have been taking for the past two years) is one which allows me to feel fine with no hypo or hyper symptoms. Strangely enough, I don't seem to need to raise it even during the winter months.

What I am basically asking is...should I accept my rather low free Ts (especially my FT4 levels), and only care about how I feel?

I know that Thiroyd contains FT4 and FT3 in different ratios than Thyroid-S, so I have been thinking lately about switching, but I really see no reason to as long as I feel fine on Thyroid-S...I am not crazy about all the fillers, but why rock the boat...?

Any input on this would be greatly appreciated.

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15 Replies

I beleive that NDT does lower t4 and with my bloods with NDT my T4 is below range. I think and I am sure someone from admin will correct me if wrong that the T3 would normally be high in range on NDT but I dont think T3 is stored so if you hadnt taken it the morning of your bloods it might well also be low. TSH is usually supressed by NDT at a good dose. It sounds like you are doing great and you have a good doctor. Can you PM me is name and contact details.

in reply to

Will do. I think the advantage of many so called Hertoghe doctors is that they are on NDT or a combination of synthetic T4 and T3 themselves, so they are likely to also have a suppressed TSH and therefore does not care about it the way mainstream doctors do...:-)

shaws profile image

I understand when on NDT (as there were no blood tests invented when it was produced) it is how the patient feels which is the priority. If you feel good, you have the answer :)

This doctor only took a blood test for the initial diagnosis and thereafter it was all about the patient and metabolism.


Dr Lowe was an Adviser to Thyroiduk.org.uk but he died prematurely due to an accident. He is a great loss to the Thyroid World:-

This is an excerpt:

ONE OF THE WORST DISASTERS in the history of medicine is the endocrinology specialty’s modern guidelines for diagnosing and treating patients whose bodies are under-regulated by thyroid hormone. These guidelines and the beliefs they’re based on have caused a worldwide public health crisis. It involves the chronic illness of scores of millions of people and the premature deaths of incalculable numbers more. Each year, billions of dollars are spent for drugs intended to control patients’ chronic symptoms; the drugs are largely ineffective and often induce adverse effects in the patients. Researchers who fail to recognize that the cause of the patients’ symptoms is under-regulation by thyroid hormone do studies looking for other causes. Since they are blinded to the real culprit, their fruitless efforts squander billions of research dollars.

We learned of this public health disaster through our study of fibromyalgia patients. Our research taught us the main underlying cause of most of the patients’ fibromyalgia symptoms: under-regulation of their bodies by thyroid hormone. After learning this, we

developed metabolic rehab, a treat ment method that helps patients recover normal metabolism. The treatment involves the use of thyroid hormone, but in ways that differ from the method the endocrinology specialty has imposed on most doctors and patients. Most patients who undergo conventional thyroid hormone therapy remain ill. In stark contrast, some 85% of patients who undergo metabolic rehab fully and lastingly recover. In this chapter, we explain how patients use thyroid hormone in metabolic rehab.


Thanks to both of you:-)

I've applied logic for years that if the TSH rises when we are undermedicated then suppression should be the aim. Having said that it was before I realised that yes we were getting to meds but not utilising them properly and that I needed to work on my conversion properly. But the really annoying thing is that many of these experts can't see that a low TSH could have credence. They won't listen to us but I wish they would listen to themselves sometime!

I started Thyroid-S myself a few weeks ago, so I'm curious to know about this too. I bought the fingerprick test to do next week! I also take first thing in the morning so was planning on not taking the Thyroid-S until after the blood draw, but was wondering how that would reflect FT3 levels. I was on levothyroxine, which had my FT4 mid range and FT3 lower range, but increasing the dose of that had little effect on FT3 but made me feel bad. Hence deciding to try Thyroid-S from Thailand.

After a week on a dose that left me feeling undermedicated and feeling like crap, then feeling over medicated on twice the dose, I've been feeling great over the last few days on a dose in between. Fingers crossed it lasts!

in reply to Crazy_CatLady

It sounds like you are a poor converter, in which case taking more T4 risks increasing your levels of reverse T3 (an inactive form of T3 which competes with and blocks the action of the active hormone free T3). That is a way for the body to get rid of unwanted/excess T4, which you risk ending up with if you take more T4 than you can convert to free T3. Been there, done that...sigh.

Good luck to you and keep us updated on your progress, will you?

Crazy_CatLady profile image
Crazy_CatLady in reply to

Thanks, will do. :-) I guess if we feel fine then we shouldn't worry too much about blood test results, but I'm always keen to know what's going on!

in reply to Crazy_CatLady

True:-) Too bad most doctors don't see it that way...but that makes forums such as this one all the more valuable...!

Crazy_CatLady profile image
Crazy_CatLady in reply to

Yes, I came to the same conclusion, poor conversion and increased RT3 (although I never got RT3 measured). Hopefully the Thyroid-S will do the trick :-)

I also take thyroid s (2 per day) . After about 5 months on NDT I was taking 3 per day when I had a blood test my FT3 was over range. I am now on two but feel extremely tired all day. That's my only symptom. After my thyroid was removed the surgeon wanted my TSH suppressed which it is at 0.08. If you feel well great don't worry too much about the blood tests.

I know many recommend you take NDT in split doses, but I've read that the T3 in NDT, unlike synthetic T3, is bound to proteins, making the body absorb it differently and more slowly compared to synthetic T3 drugs...?

helvella profile image

The value of test results seems to be in their ability to identify identify high and low levels - and changes.

You might have a body which operates very well with an FT3 of 2.9 (in the circumstances you carefully describe). Someone else might want it to be 3.0, 3.3, 3.7, 2.6, or any other number in that general area.

Next time, if you find the number significantly higher or lower, it might be a decent indicator that you are drifting away from where you felt good. But I don't think that there is any reason to upset the apple-cart to get to specific number. Remember ranges are established without looking at patients being treated and also with regard to timing, etc. They are established by looking at "healthy" people.

in reply to helvella

Thanks, as always, for great advice and info, Helvella!

helvella profile image

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