Study Shows Armour Thyroid Should Still be Considered for Some

Several studies have shown that many patients with hypothyroidism on levothyroxine replacement have low quality of life. An alternative to levothyroxine replacement for patients with hypothyroidism is desiccated thyroid that comes from pig thyroid, of which the most common brand is Armour Thyroid.

Armour Thyroid has been in use for almost 100 years (since the 1920s) although it went out of favor about 25 years ago with more doctors prescribing synthetic levothyroxine.

However recently there has been an added interest in using Armour Thyroid and other formulations of desiccated thyroid, partly because of the low quality of life some patients have on levothyroxine replacement and partly because of an interest in patients to use something they consider “more natural” and less synthetic.

Most endocrinologists and consensus guidelines by the American Thyroid Association still recommend the use of synthetic levothyroxine and to avoid desiccated thyroid, in part due to the erroneous belief that desiccated thyroid is not standardized.

In fact a 2012 publication by The Hormone Foundation, the arm of the Endocrine Society that provides information to patients discouraged use of desiccated thyroid due to this rumor that desiccated thyroid is not standardized.

In the May 2013 issue of Journal of Clinical Endocrinology and Metabolism, Huang and colleagues from the Walter Reed Medical National Military Medical Center in Bethesda, Maryland published the results of a randomized crossover study in which 70 patients completed the study and received either desiccated thyroid or levothyroxine replacement.

In the introduction to this paper they commented that the T4 and T3 content of desiccated thyroid preparations, especially Armour Thyroid, has now been standardized. They cited a paper by JC Lowe published in the journal Thyroid Science in 2009 that is not available on Medline which states that Armour Thyroid has indeed been standardized so that 1 grain of Armour Thyroid contains 38 μg of L-T4 and 9 μg of liothyronine (T3).

The 2013 study by Huang and colleagues used a conversion factor that 1 mg of Armour Thyroid was equivalent to 1.67 μg of levothyroxine to determine equivalent dosing between the two preparations. Patients were on a stable dose of levothyroxine and had a normal TSH before the study started.

Half of them were then initially given Armour Thyroid and half of them continued on the levothyroxine. Seventy-eight patients were randomized and 70 concluding the study, with 35 received Armour Thyroid at the beginning and 35 received levothyroxine at the beginning.

The dose of either the levothyroxine or the Armour Thyroid was adjusted after six weeks so that the TSH was between 0.5 and 3.0. The patients continued on that dose for an additional 10 weeks. After 16 weeks, patients were switched over to the other compound with the same adjustment at six weeks and continued for another 10 weeks.

At the beginning of the study and at the end of each 16-weeks session, the patients underwent thyroid function test, biochemical testing, memory testing (the Wechsler memory scale), a depression inventory, and a thyroid symptom questionnaire.

Researchers compared the results before and after treatment for each group.

There was not a statistical improvement in symptoms for general health questionnaires or neuropsychological testing. However there was a trend toward improvement in these tests for the group that took the desiccated thyroid compared to the levothyroxine replacement group.

There was a 2.86 pound weight loss among the group that took the desiccated thyroid compared to the levothyroxine group that was significant...

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