FDA Looking to Approve Desiccated Thyroid Extract: Commissioner

The extract is used to treat hypothyroidism.

FDA Commissioner Dr. Marty Makary in Washington on July 29, 2025. Saul Loeb/AFP via Getty Images

The Food and Drug Administration is, for the first time, looking to approve a desiccated animal-derived extract used to treat a thyroid gland problem, its commissioner said on Aug. 13.

“FDA is committed to pursuing the first-ever approval of desiccated thyroid extract, pending results of the ongoing clinical trials,” Dr. Marty Makary said on X.

“In the meantime, we will ensure access for all Americans.”

There is currently no approved desiccated thyroid extract on the market.

A spokesperson for the FDA told The Epoch Times on Aug. 14 that the agency “is committed to advancing the science needed to make more treatments available to Americans, while ensuring the public is protected from unapproved therapies.”

Desiccated thyroid extract is a medication derived from animal thyroid glands. It is one of two types of medication used by people with hypothyroidism, a condition characterized by a lack of hormone production from the thyroid gland.

About 5 percent of Americans aged 12 and older suffer from the condition.

The FDA said earlier in August that synthetic medications to treat hypothyroidism have been approved by the agency for decades and are prescribed carefully by doctors who take into account a patient’s thyroid hormone levels.

Twenty-two million patients received prescriptions for the synthetic drugs in 2024.

Desiccated thyroid extract, on the other hand, was prescribed to an estimated 1.5 million patients last year, despite that it was not FDA approved and contains compounds “that are uncharacterized for safety and effectiveness,” the agency stated.

More than 500 adverse events that followed receipt of the extract were reported from 1968 through February 2025, and multiple animal-derived thyroid (ADT) drugs have been voluntarily recalled for being too potent or not potent enough.

There’s a risk that the extract may have impurities due to the source and the way it is manufactured, officials said. If there are impurities, then patients can experience infections or other health issues after receiving the extract.

The FDA told manufacturers, importers, and distributors in an Aug. 6 letter that all ADT drugs are unapproved and that officials have found issues with the potency, uniformity, and labeling of the products.

“We believe it will require up to 12 months to safely transition patients to an FDA-approved thyroid hormone replacement product,” the FDA stated.

“FDA intends to provide adequate time to transition patients to an FDA-approved thyroid hormone replacement product before initiating action against manufacturers, distributors, and importers of ADT and unapproved ADT products intended for commercial distribution.”

In one trial, the results were similar between patients who took the extract and those who received a synthetic medication, although patients who received the extract lost more weight. Another trial also found similar results between the treatments.

Dr. George Tidmarsh, who was recently named a top FDA official, previously said that the FDA should remove desiccated thyroid extract from the market, describing it as “an unapproved, crude pig tissue extract that is proven worse than synthetic thyroid hormone and harmful.”

Some others have said the extract is better, at least for certain populations.

For postmenopausal women, “natural thyroid hormone is far superior,” Dr. Robert Malone, an adviser to the government, wrote on X on Aug. 13.