Thyroid UK

NDT Question

Hi Everyone

Do any of you know how the pharmaceutical companies extract the hormones from the porcine thyroid glands to make up their NDT? Are chemicals used for the extraction of these hormones? If so, do you know which, by any chance?......

I'm thinking Helvella (Rod) may have a useful answer here?........he's usually full of pearls of wisdom! ;-)

Thank you for any information you're able to give. :-)

11 Replies

I don't think the hormones are extracted. I thought the gland was just dried and then ground up into a powder. Fillers and binders are then added to make a standard size pill.



Hi Flower007, thank you for your answer.

How do they know then that there is the precise amount of hormone in each quantity, that they state on the NDT pot label (e.g. T4 39mcg; T3 9mcg)? Surely if they just ground it up and put in into pills there maybe some natural fluctuations in the levels of hormones in each pill/batch. I think that's the process of making the brands of glandulars that contain hormones, I think that's why they can't state how much hormone is in their products because it does vary because they're literally made from the dried gland? Please do correct me if I'm wrong.

Sorry to ask further questions and possibly complicate things! It's just something that I've been thinking about. I like being a bit of a detective and educating myself on these things. :-D


Yes, that is why one of the biggest arguments against desiccated thyroid is the chance of greater variability from batch to batch than synthetic brands.

The argument for is that our bodies do not make a precise amount of hormone every day as many external factors influence them (tiredness, emotional trauma, stress, hunger, love & happiness - lol, etc).

Therefore it is considered that our bodies will compensate and adapt to the hormones readily available.



I believe that T4 and T3 content of NDT is determined according to the protocol of the US Pharmacopeia. This requires that the T4 and T3 is measured by a sound, credible method. Originally, the method was anything but sound but the modern method is OK. The company will mix batches of thyroids from pigs and that way obtain the absolute and consistent T4 and T3 levels using the Pharmacopeia method of estimation.


Do you know what the sound and credible method of estimation is diogenes?


The Pharmacopeia lays out a detailed chromatographic method for separating T4 and T3 from each other and from everything else. Before, the earlier method was simply measuring iodine content which didn't distinguish T4 and T3.


Thank you diogenes.

And of those of us who don't know what that means...



The production of consistent potency desiccated thyroid powder requires numerous steps over and beyond the basic drying and grinding.

Each batch of powder is assayed individually.

Where necessary, modest amounts of sugar (sometimes lactose, sometimes possibly dextrose) are added as a diluent to help ensure that batches are of suitable potency. The diluents may vary from one manufacturer to another.

Various batches are selected and combined - perhaps one strong batch with two weak batches. (I know the principle but not the details. They might have to combine dozens of batches for all I know. And they have to be considering both T4 and T3 levels.)

Some source animals have seasonal variations of thyroid hormone levels. This is a bigger problem in sheep and cattle and one reason for favouring pigs as a source.

In the middle of the twentieth century, Armour laboratories used to test product on live animals. Though the laboratory assays were rather crude, this additional biological testing potentially helped to avoid large variations. (No idea if animal tests are done by Forrest or any of the other manufacturers.)

It is my belief that variations which were widely reported before the type of testing diogenes referred to have become a folklore in endocrinology. Many scoff at Nature-Throid, Erfa, ND Thyroid, Armour, etc., but I suspect this is done without actually examining the products properly. RLC (makers of Nature-Throid and WP Thyroid) claim never to have had to recall a product. Which is more than can be said for Synthroid, Levoxyl, Mercury Pharma (and its antecedents), Teva, and many other levothyroxine products which the same medics appear to accept without question.

1 like

Thank you Helvella for your very interesting and informative reply. Much appreciated for your time spent on your reply to me.


Porcine thyroid glands are dried then ground into a fine powder, hormones are not extracted.


Thank you Glynisrose for your helpful reply. :-)


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