 George Redmayne Murray of the United Kingdom first described treatment of myxedema with thyroid extract in 1891, and published a description of long-term successful treatment (28 years) of a patient with myxedema (severe hypothyroidism) in 1920 His treatment was quickly adopted in North America and Europe.The first recorded American use dates to 1891 by a woman who was still taking it 52 years later at 84 years of age 

Desiccated thyroid extract is prepared from pig thyroid glands.The glands are dried (desiccated), ground to powder, combined with binder chemicals, and pressed into pills.