Natural Desiccated Thyroid Drugs Deemed Safe

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Natural desiccated thyroid - known as NDT, thyroid extract, porcine thyroid - is a prescription thyroid drug derived from the dried thyroid gland of pigs.

Natural desiccated thyroid contains two key thyroid hormones -- 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.

For the first half of the twentieth century, natural desiccated thyroid -- namely, the brand known as Armour Thyroid -- was the only treatment for hypothyroidism. In the 1950s, a synthetic form of the T4 hormone was developed - known as levothyroxine, or l-thyroxine. Since that time, levothyroxine has been the preferred treatment of the conventional medical world. Natural desiccated thyroid has, however, remained on the market, but has drawn criticism and fire from conventional physicians and competing drug companies as being "old-fashioned" and outdated. Meanwhile a subset of thyroid patients have continued to prefer natural desiccated thyroid over levothyroxine, likely due to the presence of both T4 and T3 hormones in the natural desiccated thyroid, versus just T4 in levothyroxine.

The issue of natural desiccated thyroid, versus levothyroxine, has been controversial for decades. Despite half a century of use, after the introduction of levothyroxine, physicians frequently argued against the use of natural thyroid by stating that there weren't studies showing it to be safe or effective.


For fans of natural desiccated thyroid, there was important news for thyroid patients that came out of the Endocrine Society Annual Meeting, which took place June of 2013 in San Francisco.

According to a presentation made by Thanh D. Hoang, DO, staff endocrinologist of the Walter Reed National Military Medical Center in Bethesda, MD, natural desiccated thyroid drugs (for example, the brand names Nature-Throid, WPThyroid, Armour Thyroid, and the generic natural thyroid drug - NP Thyroid - manufactured in the Acella) are viable alternatives to what is considered the standard thyroid hormone replacement treatment, levothyroxine.

(Some of the commonly known brands of levothyroxine include Synthroid, Tirosint, Unithroid, and Levoxyl).

Dr. Hoang conducted a randomized, double blind, crossover study to compare the effectiveness of natural desiccated thyroid versus levothyroxine as a hypothyroidism treatment. The study evaluated a total of 70 patients, who ranged from the age of 18 to 65, and all had primary hypothyroidism. The patients were randomly assigned to a group that took either a natural desiccated thyroid drug, or levothyroxine, for a total of 16 weeks. The studies were blind, meaning that patients did not know which of the two medications they were receiving.

At the end of the study, the patients were asked which drug regimen they preferred. Interestingly, almost half the group -- specifically, 49 percent -- preferred the natural desiccated thyroid treatment, compared to almost 19 percent who preferred levothyroxine. About 33 percent of the patients didn't specify a preference.

Of particular interest: Dr. Hoang also reported that the patients taking natural desiccated thyroid lost approximately three pounds during the study period, compared to the patients taking levothyroxine, who did not lose any weight.

Dr. Hoang told Endocrine Today, "We didn't find any differences in the neurocognitive measurements between the two therapies...We now know that once-daily desiccated thyroid extract is a safe alternative treatment for patients with hypothyroidism who are not satisfied with levothyroxine treatment. It's an option for them to try, and also desiccated can cause modest weight loss in these patients as well.

Want to learn more about natural desiccated thyroid? Read Thyroid Patients: Do You Need T3 or Natural Desiccated Thyroid?.

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