Natural Desiccated Thyroid as Thyroid Treatment

A History of the Controversy Over Natural Thyroid Drugs

natural desiccated thyroid, NDT, Armour Thyroid, nature-throid, thyroid extract
Image Source / Getty

It's no secret that natural desiccated thyroid drugs (NDT) have been controversial for decades. NDT is a prescription form of thyroid hormone replacement and is also referred to as natural thyroid, thyroid extract, porcine thyroid, "pig thyroid," or by brand names such as Nature-throid or Armour Thyroid.

NDT was first developed back in the early 1900s and is made from the desiccated (dried) thyroid glands of animals, as a way to treat hypothyroidism, a deficiency of thyroid hormone. The earliest forms of natural thyroid came from the thyroid gland of cows, but early in the 1900s, the Armour meat company got into the field, marketing its own natural desiccated thyroid from pigs, known as Armour Thyroid. 

Because it was developed before the FDA existed, its legality as a prescription medication was grandfathered in, and natural desiccated thyroid, while regulated by the FDA, has never gone through the "New Drug Application" (NDA) process that was required of new drugs introduced to the market after the FDA was founded.

Natural desiccated thyroid contains both T4 (thyroxine) and T3 (triiodothyronine), as well as calcitonin, and other elements found in an organic thyroid gland. A normal thyroid gland produces primarily T4 (the storage hormone) and some T3, and the T4 is converted into T3, the active hormone, for use by the cells and tissues of the body.

The Rise of Synthroid

During the middle of the last century, synthetic thyroid medication came on the market. This synthetic version of the T4 hormone is known generically as levothyroxine, and sometimes referred to by the most common brand name, Synthroid. Levothyroxine became increasingly popular, and during the second half of the 20th century, it became the treatment of choice for the mainstream medical community. Physicians claimed it was more stable and consistent than natural desiccated thyroid, and that the body was able to convert T4 into the active T3 the body needed to resolve hypothyroidism.

For several decades, the vast majority of thyroid patients was prescribed levothyroxine drugs to treat hypothyroidism. But as interest grew in natural medicine in the 1980s, integrative and holistic physicians began to again prescribe natural desiccated thyroid, which had remained on the market, although with a small market share.

Some of the older physicians who had previously used natural desiccated thyroid with their patients also, switched some patients back to natural desiccated thyroid drugs Some of these patients had complained, after being switched to levothyroxine, that their symptoms had worsened or couldn't be resolved.

While many thyroid patients and physicians remained unaware that there were any options outside of levothyroxine to treat hypothyroidism, in the 1990s, awareness of NDT as an option increased, for several reasons:

  • the rise of the Internet
  • increased patient access to other patients
  • increased sharing of information among patients and practitioners

Increasingly, symptomatic and dissatisfied thyroid patients taking levothyroxine became more aware that natural desiccated thyroid drugs were an alternative to levothyroxine.

The use of these drugs increased, and some patients found that their symptoms and thyroid blood levels, were better controlled on natural desiccated thyroid, as compared to levothyroxine, or even levothyroxine plus a synthetic form of T3 (the brand name is Cytomel, and generically it's known as liothyronine.)

The controversy grew as more patients asked for natural desiccated thyroid, and more practitioners, particularly those with a more integrative focus, prescribed it. Misinformation abounded, with some doctors erroneously claiming that natural desiccated thyroid drugs were available without a prescription or were made from cows, and thus were a risk. Official treatment guidelines recommended levothyroxine and specifically discouraged use of natural desiccated thyroid drugs.

But still, as patient empowerment and knowledge increased, and as holistic and alternative medicine gained a greater foothold, the number of prescriptions for natural thyroid drugs increased. A lab, Western Research, that had made natural desiccated thyroid drugs Nature-throid and Westhroid (now WP Thyroid), was purchased by RLC Labs, and these two drugs gained greater market share as well.

The latest Clinical Practice Guidelines for Hypothyroidism in Adults, published by the American Association of Clinical Endocrinologists (AACE) and the American Thyroid Association (ATA), misrepresented natural desiccated thyroid. The concerns with the Guideline's discussion of natural thyroid are summarized in this article, but basically, they continued to erroneously suggest that NDT prescription drugs were from cows, and they tried to close the subject by saying "There is no evidence to support using desiccated thyroid hormone in preference to L-thyroxine monotherapy in treating hypothyroidism and therefore desiccated thyroid hormone should not be used for the treatment of hypothyroidism."

They failed to mention that there is no evidence to support using levothyroxine in preference to natural desiccated thyroid. The research simply hadn't been done either way, so years of habit, dogma, and marketing appeared to be the driving forces behind their recommendations, not findings from double-blind, peer-reviewed, journal published research studies.

Comparing Levothyroxine to Natural Desiccated Thyroid

A recent randomized, double-blind, crossover study compared natural desiccated thyroid to levothyroxine. The study evaluated 70 patients (ages 18 to 65) who had primary hypothyroidism. The patients were randomly assigned to either natural desiccated thyroid or levothyroxine for 16 weeks.

Concluding the study, patients were asked which regimen they preferred, and almost 49 percent preferred the natural desiccated thyroid, versus almost 19 percent who preferred levothyroxine. About 33 percent didn't specify a preference.The patients taking natural desiccated thyroid lost approximately three pounds, compared to the patients taking levothyroxine, who did not lose weight.

That research was presented to the Endocrine Society; a major and important development thyroid patients. Patients and practitioners have the right to prescribe and take whichever brand or type of thyroid hormone replacement medication works safely and best for each patient. 

A Word from Verywell

If you are interested in exploring NDT as a treatment for your hypothyroidism, keep in mind:

  • You may need to work with an integrative or holistic physician, versus an endocrinologist.
  • You should work with a practitioner who has expertise in prescribing NDT, and managing patients on NDT.
  • It is never a good idea to buy prescription drugs off-shore, without a prescription, and take them without a physician's oversight.
  • Over-the-counter glandular thyroid support supplements are not prescription NDT, and are not a substitute for prescription thyroid hormone replacement medication.
Was this page helpful?
Article Sources
  • Hoang TD. "Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism." American Thyroid Association (March, 2013).