Thyroid UK

Correct dosage NDT

As my previous post show I am finding it hard getting the correct dossage .I felt I was too high on 2grain as didn't feel well ,tired and ill like I was when I had up my NDT too much before . Today I decided to miss my meds and see how I feel as I thought if I felt worse then I would need .to up .Today I felt a lot better so am I right then that I must have been on to high a dose as and should drop by 1/4 grain although some have said drop by 1/2 grain . I feel a lot better in myself today and temperature was 37 this morning which is higer than when I was on my 2 grain as usually was 36.2 to 36.7 as varied each morning , any advice would be helpfull .

8 Replies

Maggie, I think you have to understand what is going on when you take a dose or skip a dose of your NDT. When you skip a dose you are losing only a part of the whole quantity of hormone from a blood level you have achieved after all these months. It's like having a cup of water and when you skip a dose it's like removing a tablespoon of water from that cup. (I'm not using exact dimensions). And when you add your daily dose, you are adding a tablespoon to your cup of water. And then if you only add or subtract 1/4 grain of your dose, you may only change the level by a teaspoon.

That's why it takes weeks or maybe months to be rid all of the NDT you have taken if you should stop it entirely.

You are trying to keep the level at one cup (if that is where you feel well).

I'm sure there are more accurate ways of explaining this but I hope you get the idea.


Some of us do better combining lower doses of NDT with T4. I think I may need only 1.25 grain + T4 (1 grain was too low). This post gives you a way to approximate the T4 part of your dose: This one uses a formula of 1.5 mcg/kg , but I think Rod has posted other formulas that use 1.6 or 1.7 mcg/kg. The point being that these are just STARTING approximations. Everything has to be fine-tuned. If you do not feel well on 2 grains, and you feel better on a lower dose, then you may be one who will do better on a T4 + NDT combo. You'll just have to try different combos to see how you feel. 2 grains has 18 mcg T3, and a normal thyroid gland only secretes about 6-10 mcg, so that IS a lot of T3. Most bodies produce more than 18 mcg T3, but that is from conversion from T4, not as direct T3. But some people don't convert well, so they do well on 100% desiccated. We are all so different.

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this condition is unlike other problems with your body. if you have a headache you take 75 mg of Aspirin. Each person with a thyroid problem has a different dose. You really need a blood test to see if you are on the correct dose and its take moths to settle down and feel well again. Also have you considered your adrenals it may not be your thyroxin that is causing the problems.




I'd reduce your dose very gradually not just miss a day's medication. The half life of the thyroxine is long c 6wks I think so it builds up gradually in your body and to reduce it you need to do that in a slow and measured way what you take today may not affect you for many weeks unless you feel attrocious I'd suggest you go down a quarter grain and stay there for some weeks and see how you go. I was on 125mcg Levo I started slowly swapping Levo for NDT ie over several months till I was on 1.25 grains of thyroidS. I felt loads better but after 5 mths felt I was still under medicated and slowly upped it to 2 grains which seems to be ok. I just go on how I feel and I feel a whole lot better than I ever did on levothyroxine. Perhaps it is better to be more scientific about it and do bloods and temperature etc but it seems to be so complicated when our bodies are perfectly able to let us know if they feel well or not if only we would listen to them. Doing dosage in small increments ensures it is gradual so I would say a lot safer than chopping and changing from day to day. I do agree that you should ensure you are not deficient in any vitamins and minerals as this can effect how well you can utilise the thyroxine. I find the adrenal insufficiency area difficult to understand properly and how one should treat it, but others here are very knowledgeable. Good luck with hitting that sweet spot!

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Thanks for advice ,started in Augest to change to NDT ,I was thinking of lowering by 1/4 grain for a month and see how I go . Didnt think it old take as long to get the correct dosage but will do it gradually this time .


Hi Maggiemay12!

You may find the Thyroid Patient Advocacy guidelines of interest

I used them to make my swap from Levo to ThyroidS and found them invaluable. Splitting the dose into two and taking it am and pm rather than a single dose am was especially beneficial to me.

How to fine tune ones dosage to get it optimal is very well explained.

I hope you find it helpful


Interestingly they do advise exactly what you have done - stopping for 24hrs if you have unpleasant hyper type symptoms!


What is NTD? I take synthroid what's the difference between synthroid & levothyroxine? Does anyone know?


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