NDT question about dosage


Does anyone know where I can get some good advice/information about taking NDT after coming off synthetic thyroxine please?

I have been taking synthetic T4 + T3 for the last ten years, having been diagnosed with Hashimoto's fifteen years ago. T4 alone didn't work well for me, the dose kept rising, but I still felt awful.

I was also taking Omeprazole (I have acid reflux and other digestive issues, including constipation) for as long, but gave this up last year, because I am now not absorbing nutrients properly. I had a course of 6 x B12 injections two months ago and am taking vitamin D, calcium, magnesium, enzymes and probiotics.

Two weeks ago, I started on NDT, 1/2 grain Nature-throid (on private prescription from my GP after I asked for it) but I don't have any instructions about taking it. The pharmacist couldn't help. I'm feeling marginally better, although tired (nothing new :-) so I wonder if I should just stay on this dose until my next blood test, which I expect will be next month when I see my GP?

I was on 100 mcg T4 and 20 mcg T3. I've had a look on the internet, so I know my current dose is low compared to that.

Thank you for reading this. :-)

9 Replies

  • We often see the suggestion that one grain of any of the prescription desiccated thyroid products works out to be similar to 75 micrograms of levothyroxine. The manufacturers usually suggest one grain as about 100 micrograms of levothyroxine but I think that is conservative.


    (Despite the corny site name, that really is the makers of Nature-Throid.)

    Your 100 T4 + 20 T3 (using one "conversion" factor) could work out at 160 micrograms of levothyroxine.

    Your half grain of Nature-Throid could work out at 37.5 micrograms of levothyroxine.

    Which is something like one quarter of the dose you were on! That isn't just a bit low, it is a gross under-dose.

    The chart I linked to suggests about 1.5 grains. I suggest that your doctor and pharmacist don't know what they are doing and can't read.


  • Thank you for your help, Rod.

    I think, after reading one of the links below, they may have started me on a minimal dose because some people get adverse reactions (I'm a bit prone to those, unfortunately). It would have been really helpful if they could have told me that, though. :-) It seems I should increase by 1/2 grain after the first week (oops, missed that) for three more weeks, and then increase again, until I reach my optimal dose. I'll start that today.

  • Do bear in mind that you were already taking some T3 so super-caution with respect to that constituent seems unnecessary.

    It is all very well being cautious, but under-dosing has its own set of problems. For example, there are people who get palpitations from being under-dosed. I'd put it down to ignorance rather than caution, sadly.


  • Thank you, that's a very useful chart. I stopped looking at STTM when they started to scaremonger about some research correlations, but there is obviously some interesting and valuable information on there. I appreciate you taking the time to send me the link. :-)

  • tpauk.com/forum/content.php...

    Part way down the page is a section entitled : How to Dose with Natural Desiccated Porcine Thyroid Extract

    But read the whole page anyway.

  • Wow, this is perfect, thank you. It explains my low starting dose too. Very much appreciated. :-)

  • The link I gave is outdated - the new one is :


  • Hello if you go to the website for nature throid by rlc labs they have a conversion chart of all thyroid medication.this will tell u if on 100 levo equivelent nature throid is 1 grain and so on with armour etc.i used it when i changed over.and if i remember liothyronine 5 is equivelent to 25 levo.

You may also like...