FDA to Ban Natural Thyroid (Armour, etc): Millions Will Suffer!

There are times when the FDA’s actions mystify us. Such is the case with the agency’s announcement on August 7, 2025 that it will “…take action against unapproved animal-derived thyroid medications…” The Food and Drug Administration plans to ban all natural thyroid products. These are also known as desiccated thyroid extracts (DTEs) or natural desiccated thyroid (NDT). The FDA will challenge brands such as Armour Thyroid, Nature-Thyroid,  NP Thyroid, Westhroid and Natural Thyroid. And if that isn’t enough, the agency will also prevent compounding pharmacists from creating tailored NDT formulations.

Why Patients Will Suffer if the FDA Bans Natural Thyroid:

First, you need to understand why so many people don’t do well on synthetic thyroid replacement therapy (Synthroid, levothyroxine). Despite what medical students are taught, anywhere from 15% to 20% of patients with hypothyroidism do not flourish on FDA-sanctioned synthetic thyroid pills.

The biology of thyroid hormones is more complicated than most healthcare professionals realize. We are grateful to Antonio Bianco, MD, PhD, for helping us understand the complexity of this process. Dr. Bianco is the Nelda C. and H.J. Lutcher Stark Professor in internal medicine. He is Vice-Provost for research and Chief research officer at the University of Texas Medical Branch, Galveston, Texas. We have interviewed him numerous times on our nationally syndicated public radio show. Here is a recent discussion of this critical issue. In it, we review his book, Rethinking Hypothyroidism: Why Treatment Must Change and What Patients Can Do.

Show 1330: Rethinking Hypothyroidism:
A leading thyroid researcher lays out why we should be rethinking hypothyroidism for patients who don’t respond to standard treatment.

The T4-T3 Conversion Controversy:

In a nutshell, synthetic levothyroxine is pure T4. That means it contains four iodine atoms. It is NOT biologically active! Think of synthetic levothyroxine as a prohormone also known as thyroxine. In other words, this compound does nothing to restore thyroid function by itself.

The body must remove one of those iodine atoms with enzymes called deiodinase type I (D1) and deiodinase type II (D2). When those enzymes do their job perfectly, they convert T4 into T3 by removing one iodine atom. It is T3, also known as liothyronine, that does all the work. (Thyroid endocrinology is full of alternate names. Liothyronine is also known as triiodothyronine, signaling its three iodine atoms.)

For many decades, doctors gave patients animal thyroid gland to treat hypothyroidism. Dr. Bianco describes this process brilliantly in our interview with him. It wasn’t until 1970 that researchers began to understand the T4 to T3 conversion process. When endocrinologists learned that inactive synthetic levothyroxine (T4) could be converted to the biologically active (T3) form of liothyronine, they just assumed that everyone could do this conversion. And most people (80-85%) can.

But that leaves 15% to 20% of hypothyroid patients in trouble. That’s because their deiodinase enzymes are not up to the task of removing that one critical iodine atom from thyroxine very efficiently. As a result, their bodies cannot make enough T3 naturally. And because they lack sufficient T3, they suffer symptoms of hypothyroidism. No matter how much levothyroxine (T4) their doctors prescribe, they cannot convert enough to active T3 (liothyronine). You will read Sharon’s story below describing what happens in such a situation.

If you would like to get a much more in-depth understanding of this entire process, please check out this article. It will explain why FDA’s plan to ban natural thyroid is ill advised:

“Study Reveals Why 1 in 6 Hypothyroid Patients Feels Bad on Levothyroxine Alone“
Doctors often treat an underactive thyroid (hypothyroidism) with levothyroxine alone (T4). New research suggests some people also need T3.

Symptoms of hypothyroidism may include:

• Fatigue, tiredness, apathy
• Brain fog, poor concentration
• Clumsiness
• Weight gain, trouble losing weight
• Slow pulse rate
• Dry skin and hair, brittle fingernails
• Hair loss
• Constipation
• Psychological depression
• Eyebrow loss (last third of eyebrows may disappear)
• Puffy eyes
• Hoarse voice
• Sensitivity to cold
• Elevated cholesterol levels
• Lowered sex drive

FDA’s Plan to Ban Natural Thyroid Is Hypocritical and Ill Advised!

One of the reasons that FDA says it wants to ban natural thyroid medications is:

“Generally, thyroid hormone replacement medications need to be dosed very carefully. There is only a small difference between a dose that is too low and will not work well and a dose that is too high, which can cause side effects. This means a doctor needs to monitor a patient’s thyroid hormone levels closely and adjust their medication dose precisely to keep their levels in the right range.”

One of the ways a physician can establish the best dose of thyroid medication for any given patient is, to quote the FDA, to:

“…monitor a patient’s thyroid hormone levels closely and adjust their medication dose precisely to keep their levels in the right range.”

A compounding pharmacy can create precise doses of natural desiccated thyroid (NDT) to fit a given patient’s special needs. Banning compounding pharmacists from supplying NDT contradicts the FDA’s own recommendations.

Another FDA Fallacy has to do with concerns about “safety, purity and potency.”

The agency says it is worried about:

• “Tablets made from the same manufacturing batches may not always provide the same thyroid hormone levels. Inconsistent doses can have serious consequences for patients. Too much medication can cause unwanted effects, and too little could not be effective. “

We have written extensively about the FDA’s lack of oversight of foreign-made generic drugs. Even when there are clear examples of poor quality, fraud and other manufacturing problems, the FDA has allowed such poorly made products into the country.

Here are just a small number of recent articles on this topic:

“Insiders Expose Secrets: Generic Drugs, Big Pharma, Ads and Mail Order Meds“
When whistleblowers expose secrets about drug ads, Big Pharma, mail-order meds, and generic drugs, pay attention! Pills, Profits and Perils!

“Seven Things to Know About ProPublica’s Investigation of the FDA’s Secret Gamble on Generic Drugs“
ProPublica offers this succinct summary of its investigation on the FDA’s secret gamble on poorly performing generic drug makers.

“Another Generic Drug Scandal! How the FDA Lets Us Down“
Here is yet ANOTHER mind boggling generic drug scandal. The FDA keeps worrisome data under wraps! How trustworthy are your generic drugs?

Why does the FDA worry so much about the quality of Armour Thyroid or other natural thyroid extracts while seemingly ignoring the quality of generic drugs made abroad?

One More Reason to Question the FDA’s Plan to Ban Natural Thyroid Products:

Guess who makes the best-selling brand name levothyroxine thyroid medicine called Synthroid? It just so happens to be the giant pharmaceutical firm, AbbVie, one of the world’s largest drug companies. Now guess who makes Armour Thyroid, one of the most popular forms of natural desiccated thyroid extracts (DTEs)?

It is no fly-by-night drug company. The maker of Armour Thyroid is Allergan, a subsidiary of AbbVie! So the FDA is planning to ban a medicine made by a major pharmaceutical firm renowned for high-quality products.

How Do Readers Feel About the FDA’s Plan To Ban Natural Thyroid?

Readers express fears about the FDA’s plan:

“I have learned from one of my doctors that the FDA has made a ruling to ban Armour Thyroid medications. They will require everyone who needs thyroid medication to use synthetic levothyroxine.

“I have taken both levothyroxine and Armour thyroid. I did not do well on levothyroxine, but I have done quite well on Armour. For the million or more patients in the USA who need Armour, how can we continue to get this drug?

“The FDA report says that there have been a few adverse reactions to natural pig thyroid. They claim the production is not well controlled.

“I read a report that one of the companies that manufactures levothyroxine [synthetic T4] in India has failed repeated FDA inspections but is still allowed to send the product to the USA. How is that better? I hope we can protect ourselves from shoddy manufactured products and maintain access to the natural product that works for us. Do you know how we should proceed?

“Right now, I take 30 mg Armour Thyroid and my TSH, T3 and T4 levels are just where they should be. I don’t want to mess with my thyroid by changing medicines. I am terrified of going back to levothyroxine.”

Another reader also fares well on natural thyroid compared to levothyroxine:

“My former endocrinologist had me taking 75 mcg of Synthroid due to the fact that lower doses were not making a difference. Then I experienced what felt like a heart attack with PVC’s. I immediately saw my primary care doctor who ran lab work showing toxicity from the high dose of Synthroid.

“I was referred to a cardiologist and I stopped the medication for a week and underwent a cardiac workup. It was normal and I fired my endocrinologist. I  allowed my primary care physician to treat my Hashimoto hypothyroidism with desiccated thyroid medication and was now taking 15 mg and feeling great. That was 20+ years ago. I will never go back to synthetic even if the FDA decides to pull it from the market. If I am forced to buy from Canada, I will.”

Tracy is really mad!

“I am so pissed! I need Armour Thyroid. My whole family does way better on it. I suffered for so long on levothyroxine. After 3 months on Armour Thyroid I feel so much better: nails, hair, bowels so much better! This medicine is a miracle for me. I am on disability and have to pay for it out of pocket. I go without a lot to buy the Armour Thyroid. Food banks here I come. FDA wake up! HELP!”

Sharon is angry about the FDA’s decision to ban natural thyroid:

“My insurance company forced me to take a generic form of Synthroid many years ago. I thought I was going to jump out of my skin as I had such a horrible reaction. I learned that although generics have to use the main ingredient of brand names, they can use whatever fillers they want. There goes the problem.

“I have now been on Armour Thyroid for a few years and what a remarkable difference it makes. I have more energy and no symptoms that I had with Synthroid or the generic. The FDA would like to take Armour Thyroid off of the market because it is natural. Go figure.”

In reviewing the medical literature on this topic, we found this study from Walter Reed National Military Medical Center (Endocrine Practice, Sep. 12, 2025).  The authors review a more comprehensive symptom questionnaire used to evaluate how patients fared on levothyroxine alone, DTE or combination therapy. People who had numerous symptoms on T4 alone felt significantly better on DTE, while those who felt good on just levothyroxine got no additional benefit from DTE or combination therapy.

The researchers conclude:

 “Patients on LT4, with moderate-to-severe symptoms despite normalization of TSH, could consider a trial of combination therapy.”

If you are concerned about the FDA’s plan to ban natural thyroid, why not let the agency know? The phone number is 1-888-INFO-FDA (1-888-463-6332). We could not find an email address for the appropriate division, but this information is listed on the website:

Contact Us

Mailing Address:

Food and Drug Administration
Center for Drug Evaluation and Research
Division of General Endocrinology
5901-B Ammendale Road
Beltsville, MD 20705-1266
Phone: (301) 796-2290
Fax: (301) 595-2123

Final Words:

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