07/06/2026
Dr. George Murray documented use of animal thyroid extract to treat hypothyroidism in 1891. He had noted that myxedema (swelling), characterized by the deposition of mucopolysaccharides in the dermis, causing thickening and swelling of the skin, occurred when patients had their thyroid glands removed, and that successful thyroid gland transplantation in animals prevented these symptoms.
He suspected, correctly, that hypothyroidism was the common cause of myxedema. Murray developed a method of treating myxedema by injecting a preparation of sheep thyroid gland into humans.
Results in his case study of Mrs. S after three months of treatment:
➥ Facial swelling decreased significantly
➥ Hand and foot swelling reduced
➥ Speech improved from slow and drawling to more fluent
➥ Mental activity and memory improved
➥ Physical activity increased
➥ Menstruation returned after a 4-year absence
➥ Skin became less dry, and perspiration returned
➥ Temperature normalized from consistently subnormal
By the 1930s, another thyroid preparation became commercially available—Natural Desiccated Thyroid (NDT), which is taken orally. NDT is made from livestock thyroid glands. Armour was a large producer of NDT for many decades, and the supplement is often known as Armour Thyroid.
NDT contains a protein containing both thyroid hormones (T3 and T4) in a ratio of about 1:4 of T3:T4.
T4 is the storage form of thyroid hormone, sold as levothyroxine/synthroid. It needs to be converted into the active thyroid hormone T3 to have any beneficial effect.
T4 was synthesized in 1927 and became widely available in the 1950s, and T3 was also synthesized and brought to market later.
Most people got better with NDT because it has some T3, but later lab-range errors and the widespread use of T4-only medication have led to less effective treatment of hypothyroidism with T4/levothyroxine today.
The photo is not Mrs S but before and after of another woman treated for myxedema with thyroid hormones in the form of NDT.
