What are measurable indicators of optimal NDT d... - Thyroid UK

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What are measurable indicators of optimal NDT dosage?

ak_83 profile image

I am a 35 year old male. 6 foot and 72 kg - on the skinny side yet with a reasonable under skin water retention. I have been hypo since I've been a kid. I have optimised my levels of ferritin, folate, vitamin B12 and vitamin D optimised as per some posts here. I am now trying to optimise my NDT.

What I would like to do here is to revalidate my knowledge in how I know when I have arrived at my "optimal" level.

While on equivalent of 2.5 grains my thyroid results were:

FT4: 13.2 pmol/L ( 12.8 - 20.4 ) - 5% through the range

FT3: 5.4 pmol/L ( 4.0 - 6.8 ) - 50% through the range

TSH: 1.5 mIU/L (0.40 - 3.80 )

I have also measured my heart beat at rest over a couple of days, which averages to around 55 bpm.

I have over the years tried measuring my body temperature (orally with a non-digital thermometer), but I found it quite a difficult process with a lot of fluctuations (3 times per day between drinks, meals, exercise and keeping the thermometer in for at least 5 minutes). So I'm trying to stick to things that are more consistent and relatively easy to measure.

I am still far from optimal, but better than I once was. I have now switched to 2.75 grains 3 weeks ago and anticipating switching to 3 grains and possibly 3.25 in the future (waiting 8 weeks in between switches and blood tests).

Right now, what I think I know is this. My FT3 should be 75-100% through the range. The other figures are of nearly no importance, but it's likely my FT4 will rise from where it is now to somewhere under 50% through the range. TSH is likely to go become suppressed (under the range). My heart beat should go up to 60-80 bpm. In my case I'm hoping to get at least another 10 bpm above where it is - so 65 bpm, but optimally perhaps 70 bpm.

It goes without saying that I'll be monitoring all my hypo symptoms for improvement, but it's quite difficult to remain objective in trying to measure those.

So what I would like to ask here is could you please validate my measurable targets above. Any comments much appreciated!

16 Replies
shaws profile image

The following is three Chapters produced by one of our Advisers, now deceased which may be helpful. He only took one blood test for the initital diagnosis and thereafter it was all about relief of symptoms. You will have to copy and paste onto a new page. Optimal means we have no symptoms and feel well.




janeroar profile image
janeroar in reply to shaws

This is really useful thank you shaws

ak_83 profile image
ak_83 in reply to shaws

That's interesting. Chapter 7 (the first link) is especially on point. It doesn't say which bpm to target though.

shaws profile image
shawsAdministrator in reply to ak_83

I would think an average rate re bpm would be fine- and I'm not medically qualified. Dr Lowe only took one initital blood test and thereafter it was all concencentrated upon the clinical symptoms and the relief of. He stated that Big Pharma introduced blood tests through monetary exchanges (corruption) to doctors to prescribe only levo and blood tests which have eventually overtaken the very original thyroid hormones replacements, NDT (natural dessicated thyroid hormones which was done without blood tests and doctors knew all of the clinical symptoms and we got a trial of NDT.

agree with Shaws, the blood tests keep being repeated to validate the doctors, in reality it's how you feel that's important. The only thing I would add is that you should try blood pressure as an indicator too, you won't feel good if that's skewed. If you are hypo then you will have water retention and bp may be high (although sugar is also implicated in bp). You don't tell us what other meds you are on, but you are young so maybe nothing else has been picked up yet? I think that what I am trying to say is maintain good health with good diet, and watch for counter indicators.

ak_83 profile image
ak_83 in reply to cazlooks

No other meds.

Personally, my main indicators are tinnitus and my bowels. Sorry, but it seems to work as a general guide for me. The less tinnitus and the easier my bowels, the more optimum dosed I am. Good luck with finding your "sweet spot" and hope you hang on to it!

ak_83 profile image
ak_83 in reply to serenfach

Fair enough. I don't know what my personal optimal will feel like. I've been sick probably from early childhood slowly getting worse...

serenfach profile image
serenfach in reply to ak_83

Sorry to hear that. Wishing you as good a health as you could wish for.

TSH110 profile image
TSH110 in reply to serenfach

Ha ha i’d agree!

This is a link for a US level optimal chart. However, the ranges still apply. You're correct in that your Free T4 should be at least in the 50% level or a little above 16-17. Your Free T3 should be in the upper 75% range (so 6.1 or a bit higher). In general, most feel best with a TSH around 1.0. This shows you need a dose increase.


ak_83 profile image
ak_83 in reply to Cincolo

I thought this applies on T4 only. With NDT I thought the aim is 75-100% FT3 and the rest doesn't matter that much. So FT4 may not even reach half way and TSH may end up below 1 even suppressed.

shaws profile image
shawsAdministrator in reply to ak_83

One of our (deceased) Advisers only took one blood test for the initial diagnosis. Thereafter it was all about the symptoms as they were relieved.

He always stated that blood tests and levothyroxine made lots of money for Big Pharma and considering, before blood tests and levothyroxine were introduced, we were diagnosed upon symptoms alone and given a trial of NDT how much money would be saved these days if doctors and endocrinologists took note of the clinical symptoms the patient has and be determine to relieve these rather than giving 'extra prescriptions' for remaining symptoms such as anti'depressants, pain relief, propropanol, etc.

Cincolo profile image
Cincolo in reply to ak_83

This is a very late reply. That is correct for NDT. However, some on NDT don't always feel best with the TSH below 1 (I am one of those). You may. If you increased your dose, your Free T3 should increase and TSH would decrease. I would aim for that optimal Free T3, making sure Free T4 doesn't get too high.

This guide has some useful information on finding your optimal NDT dose. I hope it helps.


I go on how I feel - I haven’t had a blood test in years 😳😊🤣. I take ThyroidS (2 grains) and a little bit of T3 (4mcg) it seems to be working well. I did do temperature but only once a day on waking it was low and I was always cold but I have warmed up since then so know I am on the right track. I don’t measure it anymore. It is supposed to be helpful but I know if I am cold without all that faff!

ak_83 profile image
ak_83 in reply to TSH110

Thanks, I'll take a look!

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