Why Your Endocrinologist May Oppose Natural Thyroid

endocrinologists, natural thyroid, Armour thyroid
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If you're not familiar with desiccated thyroid, here's a quick rundown. Desiccated (dried) thyroid is a thyroid hormone replacement drug prepared from the thyroid gland from pigs, also known as "porcine thyroid." Some of the brand names including Armour Thyroid, Nature-thyroid, and WP Thyroid.

Desiccated thyroid is a prescription drug, and it's regulated by the FDA. It has been on the market and safely used for more than 100 years.

Until synthetic thyroxine (also known generically as levothyroxine, with brand names including Synthroid, Levoxyl, and Tirosint) was introduced in the 1950s, desiccated thyroid was the only thyroid hormone replacement medication.

When synthetic thyroxine was introduced, there was a great deal of excitement about how modern it was, compared to desiccated thyroid, which was considered old-fashioned. At that time, many doctors switched patients over to the synthetic medication and never looked back. Meanwhile, synthetic thyroid – namely Synthroid – became a profitable mainstay for the various drug companies that have owned the rights to Synthroid over the years, which have included Boots, BASF, and now AbbVie, a spinoff of Abbott Labs.

All along, like many major drug companies, the makers of Synthroid have sponsored medical meetings, golf outings, symposia, research grants, and speakers' fees, and have provided free patient literature, pens, pads, mugs, and other giveaways and marketing items.

We now have several generations of doctors who were trained in medical school to understand that synthetic levothyroxine is the only acceptable thyroid replacement medication, and many know the brand-name Synthroid specifically, due to the extensive brand marketing.

Many doctors are not aware that natural desiccated thyroid is still available, or that it can be used safely to treat some hypothyroid patients. Some believe that prescribing natural desiccated thyroid is difficult. These ideas are unfortunately reinforced by negative opinions from levothyroxine sales representatives, unfounded rumors that desiccated thyroid is going off the market, and other anecdotal information.

Despite the preference for the synthetic levothyroxine, since the 1990s, natural thyroid drugs started to make a resurgence, as interest in natural medicine increased. At that time, patients who weren't feeling well on synthetic thyroid medication were also becoming more empowered and aware, thanks in part to the Internet. Patients learned that there were options – among them, desiccated thyroid drugs like Armour and Nature-throid.

Let's be clear: Several million prescriptions a year are written for desiccated thyroid, compared to more than 30 million prescriptions a year for levothyroxine. But frustrated patients who don't feel well who are coming to sites like this one, reading books, and talking to other patients. As a result, they are becoming increasingly aware that there are options beyond levothyroxine, and, that some patients feel better on desiccated thyroid medications.

An Endocrinologist's Perspective on Natural Desiccated Thyroid

Over at the Endocrine Today blog, endocrinologist and osteopath Thomas Repas, DO, FACP, FACE, CDE, did a three-part article on "Desiccated thyroid in the management of hypothyroidism," from his perspective as an endocrinologist.

It's an interesting analysis because it offers a fairly clear view of how most endocrinologists view natural desiccated thyroid drugs, and why the endocrinology community is so frequently opposed to the use of these drugs. (This is in comparison to holistic, integrative MDs, who often prefer to use desiccated thyroid because they find it works better for some of their patients.)

Dr. Repas starts out by saying that he, like his peers in endocrinology, doesn't use desiccated thyroid, because, "I believe that desiccated thyroid is antiquated therapy and should no longer be used."

He also claims that endocrinologists don't use Armour because of an "unacceptable level of variability batch to batch, often resulting in unacceptable variation in thyroid-stimulating hormone." Noting that levothyroxine also has variability from brand to brand, he states, "if we consider slight variation between various levothyroxine products to be clinically important, then the much larger variation within desiccated thyroid preparations is unacceptable."

In Part III, Dr. Repas says that while most people would not dream of "directing a cardiologist how to perform cardiopulmonary resuscitation during a cardiac arrest...otherwise reasonable people have no hesitation trying to 'teach' me about the thyroid." He then argues that the desire to be listened to and interest in natural approaches are driving the interest in natural desiccated thyroid.

Dr. Repas says his opposition to natural desiccated thyroid is based in science, but he there's a catch. Dr. Repas fails to mention that there are no double-blind, peer-reviewed, double-blind studies that compare levothyroxine to desiccated thyroid in terms of effectiveness at resolving patient symptoms. 

In fact, Dr. Repas himself admits, in the comments section of Part I:

"For the record, my greatest concern with desiccated thyroid (or levothyroxine or T3) is when they prescribed in a manner that results in long-term exogenous hyperthyroidism. If a patient is not hyperthyroid and they are doing better on one product vs. another, it is very hard to argue against that."

He also concludes Part III with an ambiguous comment:

"Finally, last week I saw a woman who had been on desiccated thyroid for decades. I explained that we now prefer levothyroxine instead of desiccated thyroid. I also quickly pointed out that her thyroid-stimulating hormone has been perfect, between 0.7 mIU/L and 1.0 mIU/L over the last several years. She had no symptoms; it was difficult for me to argue with success. After discussing and asking her what she wanted to do, she left my office still on desiccated thyroid."

When the articles were originally published, there were many comments left by patients who were enraged by them. On the one hand, Dr. Repas was trying to explain why he doesn't believe in Armour Thyroid, calling it unscientific and claiming that fans of it are engaging in "magical thinking." But Dr. Repas did not offer scientific evidence to support his claims, and he negated the real-life experience of hundreds and thousands of thyroid patients and practitioners. 

At the same time, Dr. Repas also admits, from a practical standpoint, that his primary concern is overdosing a patient to hyperthyroidism on any thyroid drug – not just desiccated thyroid. And he also admits that if a patient can be properly managed on desiccated thyroid, then he doesn't see a reason to "argue with success."

Dr. Repas won't start new patients on desiccated thyroid – even if they ask. If an existing patient on levothyroxine isn't feeling well asks to switch to desiccated thyroid, he won't do it. But if a patient is already on it and doing well, it's telling that he won't "argue with success" and will continue to prescribe the desiccated thyroid for him or her. 

In some ways, Dr. Repas is more open-minded than some endocrinologists. There are some who simply will not have any patients on a T3 drug or desiccated thyroid. Some even fire their patients who insist on natural thyroid drugs, or who won't follow directions. But Dr. Repas is also fairly representative of the perspective that we see among endocrinologists in general. Their primary concern is the "TSH normal range"—and their treatment goal is to get patients into the normal range. Symptom resolution appears to be irrelevant and takes a back seat to management of TSH levels.

A Word from Verywell

If you are being treated for hypothyroidism with Synthroid or levothyroxine alone and you still have symptoms of persistent hypothyroidism, talk to your doctor about the possibility of trying natural desiccated thyroid.

If your doctor absolutely refuses to entertain that option without offering you a very good reason that is specific to your health, it may serve your best interest to seek another opinion from a different practitioner – ideally an integrative or holistic physician comfortable with the full range of thyroid medication options—versus an endocrinologist.

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Article Sources
  • Braverman, L, Cooper D. Werner & Ingbar's The Thyroid, 10th Edition. WLL/Wolters Kluwer; 2012.
  • Garber, J, Cobin, R, Gharib, H, et. al. "Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association." Endocrine Practice. Vol 18 No. 6 November/December 2012.
  • Repas, T. DO, FACP, FACE, CDE. "Desiccated thyroid in the management of hypothyroidism: Parts I, II, III." Endocrine Today. January 2009. Online