The Use and Abuse of Thyroid Hormone

Abstract

Introduction: Thyroid hormone, in some form, has been in use for the treatment of hypothyroidism since at least the 15th century. Although thyroid hormone therapy plays an essential role in the management of hypothyroidism, it has also been misused for more dubious indications. Materials and Methods: Authors performed a search of PubMed, the American Thyroid Association (ATA) website, to include the Thyroid History Timeline that is part of the Clark T. Sawin History Resource Center, and a general internet search to identify publications and internet postings relevant to the use and abuse of thyroid hormone. Results: Documented examples of various treatments for goiter and hypothyroidism extend back to 2700 BC when seaweed was used for the treatment of goiter. In 1475, Wang Hei, a Chinese physician, reported the use of minced thyroid as a treatment for goiter. In 1891, Dr. Murray introduced the use of thyroid extract as a therapy for myxedema. Edward Kendall, PhD, at Mayo Clinic went on to isolate thyroxine in 1914 with it becoming commercially available by 1917. T3 was later isolated by Rosalind Pitt-Rivers, PhD, and Dr. Jack Gross in 1953 becoming clinically available in 1956. Various other thyroid hormone analogues, such as D-T4 and TRIAC, later became available as well. In the late 19th century, Dr. Brown-Séquard published self-experiments on the use of gland extracts as a means to improve health and restore vitality in older age. The growing indiscriminate use of various gland extracts for dubious indications led to Dr. Edward Rynearson coining the phrase “Endocriminology,” a term further popularized by Dr. Harvey Cushing as to highlight the concern about misuse and abuse of available gland extracts. Desiccated thyroid gland extract began to be used not just for goiter and hypothyroidism but also for additional “indications” such as obesity, sterility, uterine bleeding, and even feeblemindedness to name a few. In 2013, a study of over-the-counter (OTC) supplements marketed for “thyroid support” found that 9 out of 10 products contained either active T4 and/or T3 with the majority containing clinically relevant amounts. The medical literature contains multiple reports of serious adverse outcomes from exposure to supraphysiologic quantities of thyroid hormone contained in various OTC supplements. Unfortunately, the Dietary Supplement Health and Education Act of 1994 Public Law 103-417 by the 103rd Congress precludes the Food and Drug Administration (FDA) from proactively monitoring such products with the FDA only being able to act when problems are reported with a certain herb or supplement. Conclusion: Although thyroid hormone remains a cornerstone for the treatment of hypothyroidism, its misuse and abuse continue to be a source of concern. The ATA is continuing efforts to educate both health care providers and the public on the appropriate use of thyroid hormone and potential risks with its misuse. No competing financial interests exist. Video endocrinology abstract for the use and abuse of thyroid hormone video endocrinology. The work for this video was independently performed by Drs. Bernet and Cappola using the methods and materials as described. The updated abstract with requested changes is being submitted. Runtime of video: 10 mins 34 secs