http://www.aace.com/pub/thyroidbrochures/pdfs/Hypothyroidism.pdf
American Association of Clinical Endocrinologists
Hypothyroidism (underactivity of the thyroid gland) occurs when the thyroid gland produces less than the normal amount of thyroid hormones. The result is the “slowing down” of many bodily functions. This fact sheet provides information for patients on hypothyroidism, including symptoms, causes, diagnosis, and treatment.