It is a source of thyroid hormone for those with hypothyroidism or an under active thyroid gland. Hypothyroidism, or an under active thyroid gland, is a common endocrine problem and requires lifelong treatment with thyroid hormone pills. Untreated hypothyroidism is associated with a wide variety of symptoms, many of which are non specific. In particular, memory problems and depression (psychometri
c problems) as well as weight gain are very common symptoms in hypothyroidism but also have multiple other non thyroidal causes as well. Levothyroxine is the main thyroid hormone produced by the thyroid gland and the synthetic form is the most common form of thyroid hormone replacement therapy. Prior to the availability of the pure Levothyroxine, desiccated animal thyroid extract was the only treatment for hypothyroidism. Today, some individuals prefer desiccated thyroid extract as a more “natural” thyroid hormone. In addition, some patients who continue to have symptoms of hypothyroidism when taking Levothyroxine report improvement in these symptoms when switched to desiccated thyroid extract. This study was performed to compare Levothyroxine to desiccated thyroid extract in terms of thyroid blood tests, changes in weight, psychometric test results and patient preference.