Desiccated Thyroid

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Desiccated Thyroid

Desiccated Thyroid (NDT) is a treatment for hypothyroidism developed from the thyroid glands of animals. Studies have shown that oral use of Desiccated Thyroid may lower the body's immune response against the thyroid. In some studies, consuming NDT for 6-8 weeks has been shown to reduce antibody levels to negligible levels.

Medical Uses

Some practitioners suggest using NDT for longer periods. This stems from beliefs about T3 absorption. T3, a compound found in natural thyroid reaches peak absorption within 4 – 8 hours after consumption.

Structure of Thyroid hormones.png

The theory is, NDT taken 2x daily maintains a high T3 absorption rate after the initial 4-8 hour peak. Others believe the excretion of T3 peaks will actually peak between 1 – 3 days not 4-8 hours. Proponents believe NDT can be taken once daily and the results will be the same. The believe the release of thyroid hormones corresponds to the circadian rhythm, with most T3 released during the late evenings and early morning. By consuming NDT before bed or early in the morning, the results will mimic the function of a normal thyroid. They believe twice daily ingestion is not recommended, because it ignores the body’s excretion levels. There is a difference between “absorption” and “metabolism” – how quickly a substance comes in and how quickly it goes out. In most instances, a discrepancy exists between the dosage amount not the treatment itself. Some practitioners have concluded that, with a correct dosage, reverse T3 is apt to fix itself.


T3/T4 ratios about:

  • The Liver
  • The Kidneys
  • The Intestinal Tract
  • The Detox Pathways
Thyroid System.png

When consuming excessive dosages of thyroid hormone, T3 will exit the body faster than T4. Too little, and the body will hold onto T3 longer. In terms of how the ratios are found in NDT, compared to the body, some suggest a 4:1 ratio is too low, that humans require a 10:1 ratio. The debate focuses on the question: what is meant by ratio?” Does it refer to:

  • What is in the thyroid?
  • What is in the blood?
  • What is in the cell?

The thyroid is at the same ratio as NDT, the bulk of it bound up in carrier proteins. The body has the ability to unbind and “convert”. With the right dosage, NDT can be used effectively. The question then becomes: “how much desiccated thyroid is right for the individual?”

When running the following tests for individuals consuming NDT:

  • TSH
  • Free T3
  • Free T4

Some practitioners may notice high T3 levels. This may lead to the conclusion to reduce the dosage due to the high test ratio. The root challenge, however, may be the timing of the test itself. Taking a blood test immediately after consuming a NDT tablet, TSH and Free T4 may remain normal, however, it can make the Free T3 score appear excessively high. This is a question of timing. NDT has 0.17 - 0.23% iodine by weight. People with thyroid disease improve with 100 - 300 micrograms of iodine total (and most diets have at least 100 micrograms). 1 grain (60 - 65 mg) of NDT is equivalent to about 130 micrograms of iodine. That is approximately 230 micrograms of iodine from NDT and diet alone. It is not necessary to consume iodine with NDT, as enough comes rom the combination of diet and NDT. Adding extra iodine may push levels above 300 micrograms, slowing the thyroid, and should be avoided. Researchers who believe NDT is not safe for those with thyroid cancer are making a point about TSH. The goal is to keep TSH on the lower side. A higher TSH level can stimulate thyroid cancer cells and cause them to grow. Other researchers question this assertion because NDT suppresses TSH. While some brands of NDT are better standardized than others, well-standardized brands make it easier to keep TSH in check. NDT and Pregnancy: Those who need thyroid replacement can safely use natural thyroid during pregnancy. Blood levels fluctuate more during pregnancy and it is important to test more frequently (regardless of which type of medication is used). It is also acceptable to have slightly lower TSH scores during pregnancy.


Prior to the 80's, there were more doctors prescribing NDT than those prescribing Synthroid. The means of standardizing hormone was based on iodine content. Years ago, that was more difficult to do using NDT than Synthroid – because science could not guarantee the quantity of active hormone present. This led to cases of people not receiving the amount of active hormone needed. Ultimately, this led to a change in the guidelines for how hormone treatments would be standardized. There have been multiple recalls for synthetic versions of thyroid over the years, upwards of a dozen in the last decade. This is due to poor quality control and inconsistency in the manufacturing process. In the last 15 years, there has been one voluntary recall of NDT. NDT has earned a better track record of helping patients over a longer period than Synthroid. Synthroid – standardized to within 5% of prescribed recommended dosage. NDT – there are brands which are standardized to less than 2% variability.


There have been double-blinded studies comparing the results of natural thyroid against T4-only medications. The results showed that those on natural thyroid lost weight more easily than those on T4 only[1]. When asked which pill they liked better, roughly 3 times as many patients preferred natural thyroid, even though they did not know which one was which. According to a recent survey of over 12,000 people on treatment for hypothyroidism, 29% were taking natural desiccated thyroid If anything this group would be less likely  then others to use natural thyroid, specifically because the survey was hosted by the American Thyroid Association (which recommends T4 treatment over natural desiccated thyroid)[2].