One of the early methods of treating an under active thyroid was to fry sheep’s thyroid glands and eat them with currant jelly or brandy. This was considered preferable to the previous treatment of grafting sheep’s glands beneath the skin of thyroid patients or injecting thyroid extract (1).

In 1894, E. Merck, introduced one of the first thyroid preparations in the world (Triiodothyronine siccatum) (2). According to Burgess a woman in the US was first treated for hypothyroidism with thyroid extract in 1896. She began taking it when she was 39 years old, and continued treatment for the rest of her life until she died at age 91(3).

Natural desiccated porcine thyroid extract contains Thyroxine (T4) and Triiodothyronine (T3) hormones, as well as T2, T1 and calcitonin. T2 is considered necessary for production of the deiodinase enzyme that helps convert T4 into T3. T3 is the active hormone that regulates the metabolism and is of short duration in the body. T4 has a much longer half-life in the body. T1s physiological role was still being evaluated until very recently when it was found that T1 has an influence on the electrical input and charge of the brain and various mental disorders, including multiple sclerosis and Lou Gehrigs syndrome, which can be a result of not enough T1 to recharge the brain. (4)

New findings research suggests that although the compound, known as T1 amine, is a derivative of thyroxine, an essential thyroid hormone that influences development, body temperature, metabolic rate and cardiac performance, it has the opposite effect of thyroxine. (5). This research also suggests that T1 amine affects several organ systems. Consequently, if its molecular and cellular actions can be precisely described, physicians will be in a better position to treat a variety of cardiovascular and endocrine diseases, as well as mental health disorders. said David Grandy, Ph.D., Associate Professor of Physiology and Pharmacology, and Cell and Developmental Biology in the OHSU School of Medicine. “here we thought we knew thyroid hormone so well, only to find out there’s this whole new aspect of it,” said Grandy, co-author of a study published in an online edition of the journal Nature Medicine. T1 amine’s normal function in the body may be to counteract, or keep in check, thyroid hormone’s actions.” (6)

For almost 60 years, desiccated porcine thyroid was the only thyroid treatment and was used successfully from 1894 until 1958, when synthetic T4 only medications first appeared on the market. Since then, doctors have increasingly viewed desiccated thyroid as old fashioned and obsolete. Unfortunately, teaching about the use of natural thyroid extract in medical schools stopped suddenly in 1975, and many doctors are untrained in its use. Many patients on Internet support groups for hypothyroid patients have reported that their doctors have never even heard of desiccated thyroid.

Doctors obtain their information about drugs mainly from universities and from pharmaceutical companies. When a medical treatment with a long history of success is relegated in favour of one that sometimes works, but is overall less effective and is more expensive, doctors and patients have a serious problem.

Around about the same time that natural desiccated thyroid was relegated in favour of synthetic preparations, there was a similar argument made for infant formula over breast milk. Infant formula was marketed as being superior to natural mother’s milk, and mothers who nursed their babies instead of feeding them formula were seen as perhaps less well informed. That situation has turned around completely since then. However, the belief that synthetic T4 is superior to natural desiccated thyroid, which contains all the thyroid hormones, still exists among endocrinologists and general practitioners.

The question arises about how these doctors got the impression that desiccated thyroid is unstable. The following quote from the bible of thyroid treatment, Goodman and Gilmans The Pharmacological Basis of

Therapeutics, provides some light on this question.

“Several years ago (1963) a large batch of material came into the hands of a number of distributors in the United States and Europe and, although of proper iodine content, it later proved not to be thyroid extract at all. This episode gave desiccated thyroid a bad name because several publications about the unreliability of thyroid extract appeared before the hoax was uncovered”

The best-known brand name of desiccated thyroid is Armour Thyroid, manufactured by Forest Pharmaceuticals Inc. in the US. Armour Thyroid and several other thyroid medications were grand fathered in when Congress passed the Kefauver-Harris Drug Efficacy Amendments of 1962, to tighten control over drugs. Before marketing a drug, firms had to prove safety and effectiveness for the products intended use.

The requirement was applied retroactively to 1938, when the FDC Act was passed. Pre-1938 drugs were allowed because they were generally recognised as safe and effective, provided no evidence to the contrary developed. Too much evidence to the contrary developed concerning the levothyroxine products and the FDA decided none of them was generally recognised as safe and effective, so the levothyroxine products lost their grand fathered privilege and had to go through the NDA process. Armour thyroid retains its grand fathered status since no evidence to the contrary has developed concerning its safe and effective status.

Until around 1970, the hormone concentrations of thyroid medications were titrated based on iodine content, but since then, they have all (including desiccated thyroid) been assayed by their hormone content. However, desiccated thyroid has been assayed the same way as other thyroid hormone medications for several decades (7) and it is recalled far less often for stability issues than its synthetic counterparts are. For details, see a 2003 newsgroup post that compares FDA recalls of different thyroid medications (8).

Dr Raymond Peat states, When synthetic T4 first became available, and in healthy young men it acted “like the thyroid hormone”, older practitioners recognized that it was not metabolically the same as the traditional thyroid substance, especially for women and seriously hypothyroid patients, but marketing, and its influence on medical education, led to the false idea that the standard Armour Thyroid USP wasn’t properly standardized, and that certain thyroxine products were, despite the fact that both of these ideas were shown to be false” (9)

When NHS medical practitioners are asked by patients why they are not prescribing Armour Thyroid for patients who are unable to tolerate T4 (Levothyroxine) typical responses are

1. Armour Thyroid was found to have had potency problems in the past
2. Armour Thyroid is an unreliable preparation in terms of active thyroid.
3. There is no adequate quality control.
4. The Medicines Control Committee will not allow this product to be licensed because of previous potency problems.
5. Thyroxine is the only medication which provides steady hormone levels.
6. Because of issues surrounding “mad cow disease” and other ailments, some are reluctant to offer animal based therapy to patients when a safe, effective well-studied synthetic preparation is widely available.

As determined by Armour Pharmaceutical Company and other participating laboratories, the liothyronine and levothyroxine content in Armour thyroid is well within the specifications set by the U.S. Pharmacopoeia. The precision of the assay procedure as determined by Armour, Eli Lilly, and the FDA is considerably better than that reported by Pharmaceutical Basics (10).

What many general practitioners fail to recognise is that the thyroid powder that contains the active ingredients for Armour Thyroid is derived from the thyroid glands of ‘grain-fed’ pigs and hogs. The USDA changed the requirements about feeding ground animal remains to pigs several years ago. The porcine thyroid glands that go into Armour Thyroid tablets are only derived from animals that do go into the US food supply. If any animal were rejected from the food supply, its thyroid gland would never get into Forest Pharmaceuticals product. Armour Thyroid has been on the U.S. pharmaceutical market for over 100 years and there are no reports of any Armour Thyroid patient ever contracting CJD”.

As some endocrinologists imply, T4 replacement (and T4/T3 replacement, which they discourage) will indeed work well for some hypothyroid patients. For others, however, synthetic replacement therapies are clearly ineffective. Armour is highly effective for many hypothyroid patients, who often have lingering symptoms on synthetic medication. It is absorbed more completely and more consistently than pure T4 because all the hormones are protein bound, which is the natural way for the hormones to be absorbed. In the natural, desiccated form, T3 appears to spread out its effects more evenly, causing fewer of the ups and downs that patients often experience with synthetic T3. For many patients, taking desiccated thyroid instead of T4 alone or even a T4/T3 combination relieves many symptoms that were not reversed previously

Armour Thyroid does not have the stability problems those synthetic T4 medications are known for. It is remarkably uniform and well absorbed and the potency is sufficiently standard that variation cannot be detected clinically (11). It is a highly satisfactory preparation for clinical use and for most purposes; desiccated thyroid is to be preferred to any other type of thyroid preparation for many people (12). A 2001 study that apparently received little notice proves what thyroid patients have been saying for years desiccated thyroid is more effective in relieving hypothyroidism symptoms than the synthetic hormones (13).

Today, The Endocrine Society’s membership consists of over 11,000 scientists, physicians, educators, nurses and students, in more than 80 countries. As this Society has previously undertaken trials into synthetic T4 v T3, it should not be impossible for them to conduct a large, multi-centre, double blind, randomised, controlled trial to prove the efficacy or otherwise of T4 v T4/T3 combination v natural desiccated porcine thyroid extract (Armour Thyroid). Patients suffering from an under active thyroid living in the UK who have benefited from switching from synthetic to natural thyroid extract (Armour) would undoubtedly be astonished and dismayed to read the Endocrine Societys trial report which indicated once again that synthetic T4 alone provides the only answer to this condition (14).
References:

1. George R. Murray, M.D., D.C.L., F.R.C.P., The Life History Of The First Case Of Myxoedema Treated By Thyroid Extract British Medical Journal; March 13 1920:359-360.
2. Merck Thyroid History http://www.thyrolink.com/service/history.htm
3. Burgess AM. Myxoedema, Controlled by Thyroid Extract for 52 years: Case. Ann Int Med 1946;25:146-150
4. D. A. Versendaal and Dawn Versendaal-Hoezee “Contact Reflex Analysis” Hoezee Marketing, 1993, p. 33.
5. 3-Iodothyronamine is an endogenous and rapid-acting derivative of thyroid hormone Katherine Suchland, Paul Kruzich, Dane Crossley II and James Bunzow, Department of Physiology and Pharmacology, OHSU; Matthew Hart, Department of Pharmaceutical Chemistry and Cellular & Molecular Pharmacology, UCSF; Grazia Chiellini, Sabina Frascarelli, Simonetta Ronca-Testoni, Riccardo Zucchi, Dipartimento di Scienze dell’Uomo e dell’Ambiente, Sezione di Biochimica, Universita di Pisa, Italy; Yong Huang and Emil Lin, Department of Biopharmaceutical Sciences, UCSF; and Daniel Hatton, Department of Behavioral Neuroscience, OHSU. Oregon Health & Science University, the University of California, San Francisco (UCSF) and Universita di Pisa, Italy. Nature Medicine 10, 638 642 (2004) Published online: 16 May 2004,http://www.nature.com/nm/journal/v10/n6/abs/nm1051.html
6. Blumberg KR, Mayer WJ, Parikh DK, Schnell LA: Liothyronine and levothyroxine in Armour thyroid. J Pharm Sci 1993; 76: 346.
7. FDA Enforcement Report Index http://www.fda.gov/opacom/Enforce.html
8. Letter from Raymond Peat,Independent Research, Eugene,Oregon. http://bmj.bmjjournals.com/cgi/eletters/314/7088/1175
9. Basier VW, Hertoghe J, and Eeekhaut W. Thyroid Insufficiency. Is Thyroxine the Only Valuable Drug? J Nutr Environ Med 2001;11:159-166.
10. Determination of Liothyronine and Levothyroxine in Thyroid Preparations by Liquid Chromatography: Steven L. Richheimer and Charlotte B. Jensen. Received February 14, 1985, from the Quality Control Laboratory, Pharmaceutical Basics, Inc., Denver, CO 80223. Accepted for publication November 14, 1985
11. Gilman AG. Page 1479 in: Goodman and Gilman’s the Pharmacological Basis of Therapeutics. 4th ed. The Macmillan Company, 1970.
12. Salter WT: Symposium on Hormones. New Engl J Med 1941;709
13. Basier VW, Hertoghe J, and Eeekhaut W. Thyroid Insufficiency. Is Thyroxine the Only Valuable Drug? J Nutr Environ Med 2001;11:159-166.
14. (Sawka.A. et.al.Does a Combination Regimen of Thyroxine (T4) and 3,5,3Triiodothyronine Improve Depressive Symptoms Better Than T4 Alone in Patients with Hypothyroidism? Results of a Double-Blind, Randomized, Copntrolled Trial, Journal of Clinical Endocrinology and Metabolism, JCEM 2003 88: 4551-4555)