Natural Desiccated Thyroid as Thyroid Treatment

The Controversy Over Armour, Nature-throid, Natural Thyroid, and NDT

Research in 2013 says that natural desiccated thyroid drugs are a safe alternative to levothyroxine in treating hypothyroidism.. Istockphoto

It's no secret that natural desiccated thyroid drugs - a prescription form of thyroid hormone replacement - have been a controversy for years in the thyroid community. First developed back in the early 1900s, natural desiccated thyroid --  also referred to as NDT, natural thyroid, thyroid extract, porcine thyroid, or by one of the brand names-- is a medication that was developed from the dried thyroid gland of animals, as a way to treat hypothyroidism.

Hypothyroidism is an insufficient amount of thyroid hormone production in the body.

The earliest forms of natural thyroid came from the thyroid gland of cows, but the Armour meat company got into the field, marketing its own natural desiccated thyroid from pigs -- porcine thyroid - 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 is required of new drugs introduced to the market since 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 -- known generically as levothyroxine, and sometimes referred to by the most common brand name, Synthroid - was developed. Levothyroxine is a synthetic form of the T4 hormone. Levothyroxine became increasing popular, and during the second half of the 20th century, it became the treatment of choice by the mainstream medical community.

Physicians claimed it was more stable and consistent than natural desiccated thyroid, and that the body was able to convert straight T4 into the active T3 the body needed to resolve hypothyroidism.

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

Some of the older physicians who had previously used natural desiccated thyroid with their patients, returned some patients back to natural desiccated thyroid drugs, because those patients complained, after being switched to levothyroxine, that their symptoms had worsened or couldn't be resolved, and found that some patients simply did better on natural thyroid.

While many thyroid patients -- and physicians -- remained unaware that there were any options outside of levothyroxine to treat hypothyroidism, in the 1990s, with the rise of the Internet, and increased access to both other patients, and sharing of information among patients and practitioners, some symptomatic and dissatisfied thyroid patients on levothyroxine became increasingly 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 with adding a synthetic form of T3 (the brand is Cytomel, generically it's known as liothyronine.)

As more patients asked for natural desiccated thyroid, and more practitioners -- particularly those with a more integrative or holistic focus -- prescribed it, the controversy grew. 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 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, was purchased by RLC Labs, and these two drugs gained greater market share as well.

As recently as late 2012, the 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. I summarized the concerns with the Guideline's discussion of natural thyroid in this editorial, but basically, they continued to suggest that there were prescription drugs of bovine (cow) origin -- there aren't -- and 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."

What did they fail to mention? 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 -- not double-blind, peer-reviewed, journal published studies -- were the driving forces behind their recommendations.

Comparing Levothyroxine to Natural Dessicated 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 and his presentation of that research to the Endocrine Society was a major step, and an important one, for thyroid patients. Patients have the right to be prescribed -- and practitioners have the right to prescribe -- whichever brand or type of thyroid hormone replacement medication works safely and best for each patient. 



Hoang TD. "Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism." American Thyroid Association (March, 2013).

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