The uncertain future of 130 years old Natural Desiccated Thyroid is challenged by the U.S. FDA.
For people with untreated hypothyroidism, that fog can be very real and life-threatening. And for more than a century, millions of patients have relied on one treatment to clear it: Natural Desiccated Thyroid, often called NDT/DTE.
Today, however, this historic medication is part of an ongoing regulatory conversation that could shape its future availability. To understand why, we have to go back more than 130 years.
The Breakthrough That Started It All (1891)
In 1891, when physician George Redmayne Murray made a remarkable discovery. He treated a patient suffering from severe hypothyroidism using thyroid extract derived from animal glands.
At the time, hypothyroidism could cause profound fatigue, mental slowing, weight changes, and serious health complications. Murray’s therapy, an early form of thyroid hormone replacement, offered the first real relief.
By the early 1900s, thyroid extract therapy had spread worldwide. This treatment eventually became known as Natural Desiccated Thyroid (NDT). Made from porcine thyroid glands, it naturally contains both primary thyroid hormones:
T4 (thyroxine)
T3 (triiodothyronine)
For decades, this combination became the standard treatment for hypothyroidism.
1938 The Era of Modern Drug Regulation
In 1938, the U.S. Food and Drug Administration gained expanded authority through the Federal Food, Drug, and Cosmetic Act. This law established the modern system for drug safety and approval in the United States.
However, many medications already widely used, including thyroid extract, had existed long before these rules were created. As a result, some older therapies continued being used without going through the newer approval processes designed for modern drugs.
The 1970s The Rise of Synthetic Thyroid Hormone
A major shift occurred in the 1970s when synthetic thyroid medications became widely available. One of the most commonly prescribed treatments became Levothyroxine, a laboratory produced version of the T4 hormone.
Doctors increasingly preferred synthetic medications because they allowed:
Consistent manufacturing
Standardized dosing
Easier monitoring
For many patients, levothyroxine worked well. But others reported that they felt better with therapies that contained both T3 and T4.
Because of this, natural thyroid medications such as Armour Thyroid and NP Thyroid continued to be prescribed.
2019 Shortages Begin to Raise Concerns
In 2019, the natural thyroid market experienced major disruptions when several manufacturers began facing supply shortages and production issues.
Pharmacies across the United States reported difficulty keeping certain NDT products in stock. For patients who depended on these medications, the shortages created uncertainty about long term availability.
2020 to 2024 Recalls and Manufacturing Challenges
Between 2020 and 2024, multiple NDT products experienced recalls due to potency inconsistencies. Some batches contained higher or lower levels of thyroid hormone than expected.
These quality issues brought increased attention from regulators and highlighted the importance of consistent manufacturing standards.
2025 to 2026 Renewed Regulatory Focus
More recently, the U.S. Food and Drug Administration has been reviewing older medications that entered the market before modern approval pathways existed.
Manufacturers of these products may be required to pursue updated regulatory approvals to demonstrate:
Consistent potency
Manufacturing quality
Safety and effectiveness
Earlier discussions suggested that companies might have several years, possibly until around 2029, to complete these steps. However, more recent regulatory developments suggest that enforcement efforts could begin sooner, with increased scrutiny expected by 2026.
A Conversation That Continues
The discussion surrounding thyroid medications today reflects two important priorities in healthcare.
The Official Stance: They claim it’s about "safety and consistency" in a biological product. The Reality: By reclassifying NDT as a "Biologic," they are creating a regulatory mountain that many manufacturers simply can't climb.
International NDT Thyroid-S: These brands, primarily manufactured in Thailand by companies like Sriprasit, have long been the "secret weapon" for patients when US supply chains fail. While they aren't FDA-approved, they are natural desiccated thyroid products that many find just as effective as their domestic counterparts.
Thyroid Glandular Supplements: Sold over-the-counter as "bovine thyroid" or "porcine thyroid" support, these glandulars are marketed as dietary supplements rather than medications. Because they aren't "drugs" in the eyes of the law, they often bypass the prescription shortages entirely.
For millions of people around the world who are relying on natural desiccated thyroid, losing it isn’t just a setback it can be life-threatening, reversing the stability they’ve fought to achieve.
