Will the FDA Ban Armour and Other Natural Thyroid Extracts?

Levothyroxine, a synthetic version of the thyroid hormone known as T4, is at or near the top of the list of most prescribed medications. Millions of Americans need to take this medication because their own thyroid glands don’t produce enough. While the majority of people on levothyroxine do pretty well on it, some people find they still have symptoms of an underactive thyroid. Among them, a number have reported that they feel better on desiccated thyroid gland such as Armour. It comes as a shock, though, to learn the FDA has not approved these old-fashioned medications.

Will the FDA Ban Armour and Other Natural Thyroid It Has Not Approved?

On August 7, 2025, the Food and Drug Administration announced that it would be demanding the elimination of natural thyroid treatment, otherwise known as desiccated thyroid extract (DTE) or natural desiccated thyroid (NDT). Experts estimate that 1.5 million patients will be impacted by this ban.

The agency justifies this action on the grounds that the:

“FDA has concerns with the safety and effectiveness of the unapproved animal-derived thyroid medications, which have not been reviewed by FDA to ensure safety, purity and potency, and may have quality and dosing issues.”

Unless a manufacturer of natural thyroid medication can prove to the FDA’s satisfaction that its formulation works, the product will disappear from pharmacy shelves sometime during the summer of 2026.

Why a Ban of Natural Thyroid Products Worries Us:

We have some serious objections to the FDA’s action. Doctors have been treating patients with hypothyroidism for over 100 years. For much of that time they used natural thyroid supplements. Synthetic thyroid (levothyroxine) was not available until 1970.

Hypothyroidism makes people feel bad. Patients experience fatigue, brain fog, constipation, dry skin, brittle fingernails, clumsiness, difficulty losing weight, depression, high cholesterol and many other symptoms.

Many endocrinologists aim to normalize TSH, thyroid stimulating hormone. They believe that synthetic levothyroxine such as Synthroid is superior to desiccated thyroid extract for this purpose. But studies in recent years have shown that some patients feel better on natural products. There is now research to support their experience.

Why Do Some Patients Feel Better on Natural Thyroid?

An analysis published in the Journal of Clinical Endocrinology and Metabolism (June 20, 2025) showed that hypothyroid patients treated with levothyroxine alone are more susceptible to dementia and early mortality than people taking DTE.

This study will come as a shock to the FDA. That’s because it suggests that natural thyroid may be better for treating hypothyroidism than synthetic levothyroxine.

Dr. Bianco explains:

We spoke with the senior author on this study, Dr. Antonio Bianco. He explained that DTE contains two different thyroid hormones, T4 and T3 (liothyronine). Levothyroxine is only T4. Doctors expect the body to convert inactive T4 to the active form, T3. This research suggests that the conversion is not always as effective as anticipated.

As many as 20 percent of hypothyroid patients have an underactive deiodinase enzyme. Because it doesn’t convert T4 to T3 efficiently, these folks don’t thrive on T4 (levothyroxine) alone.

In the 20-year retrospective study Dr. Bianco and his colleagues conducted, DTE was safe and effective–more effective, in fact, than synthetic levothyroxine. He points out that one of the most common medicines prescribed for people who are also taking levothyroxine is a statin (Endocrine Practice, Aug.5, 2025).

Low Thyroid Linked to High Cholesterol:

It seems that even when TSH is normal, thyroid hormone levels (especially T3) in the liver may be a bit low. As a consequence, hypothyroid people tend to have elevated cholesterol. How do doctors respond? Usually, they write a prescription for a statin rather than switching the patient to a synthetic combination of T4 and T3 or natural thyroid hormone. People on DTE don’t seem to need statins as often. When will the FDA acknowledge these facts and change its plan? Why has the agency not approved the natural products to treat thyroid problems?

Trying Out Armour for Hypothyroidism:

Q. My doctor is cool with anything reasonable that I want to try. So when I asked for a scrip for Armour Thyroid instead of the levothyroxine (Levoxyl) I’ve been taking for years, he agreed. I have been on Levoxyl ever since my thyroid was removed to treat Graves’ disease.

I’m on Medicare and my insurance denied it because the FDA has not approved it. It’s inexpensive, so I paid cash for it, just $20.

My poor daughter, who has hypothyroidism due to Hashimoto’s, asked her endocrinologist and the reaction was swift. “NO! I don’t prescribe Armour to anyone I care about. Tell your mother not to take it.”

I’m taking it anyway, and in another six weeks I’ll be getting labs done. If it’s working, great. If not, I return to Levoxyl. I haven’t noticed any difference, but I’ll go with the bloodwork.

Are you aware the FDA has not approved this? Apparently, it’s some kind of control over how much of each hormone (T3 and T4) the pill contains.

Why the FDA Has Not Approved Desiccated Thyroid Extract:

A. Armour Thyroid and other brands of desiccated (dried) thyroid extract (DTE) are made from pig thyroid glands. Before there was synthetic thyroid (Synthroid or levothyroxine), doctors relied upon DTE to treat people with underactive or missing thyroid glands. These products were grandfathered into pharmacy practice.

According to the official prescribing information for Armour Thyroid,

“This drug has not been found by FDA to be safe and effective, and this labeling has not been approved by FDA.”

However, the description of the drug specifies exactly how much T3 (liothyronine) and T4 (levothyroxine) each grain of thyroid extract contains. We suspect that the reason FDA has not approved these drugs may be linked to the cost of applying for New Drug Approval. Quality control in the mid-20th century was lax, and the drug got a bad reputation among endocrinologists for that reason. We understand that has improved, but some experts are still leery of prescribing it. Nonetheless, endocrinologists should be personalizing thyroid treatment (Frontiers in Endocrinology, July 9, 2019).

Learn More:

Most people do well on medications such as Levoxyl or Synthroid with levothyroxine alone. Some, however, report that they feel much better on Armour or another desiccated thyroid extract, presumably because it contains T3 as well as T4. You can learn more about this and why it’s important in our eGuide to Thyroid Hormones.  You may also wish to listen to our interview with Dr. David Cooper, Director of the Thyroid Clinic at Johns Hopkins. It is Show 1162: How to Treat Common Thyroid Problems. In it, we discuss Graves’ disease and hyperthyroidism as well as Hashimoto’s and hypothyroidism. We also discussed how genetic variations might explain who feels better on desiccated thyroid extract in Show 1096: What You Need to Know About Treating Thyroid Disease.