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).