Is Armour Thyroid Being Discontinued? FDA Status Update, September 2026
Natural desiccated thyroid (NDT) medications such as Armour Thyroid and NP Thyroid remain legal to prescribe and fill in the United States as of September 2026. The FDA announced plans in August 2025 to remove them from the market, then withdrew the removal deadline in March 2026. This article tracks the full timeline, the agency's stated reasons, the current rules, and the insurance changes that now affect access.
Key Takeaways
- In August 2025 the FDA told manufacturers of animal-derived thyroid products to stop marketing within about 12 months and advised patients to transition to approved drugs.
- The FDA's core reason is regulatory. It classifies desiccated thyroid as a biological product, which requires a Biologics License Application that no NDT manufacturer holds.
- On March 11, 2026, the FDA replaced its letter. The deadline and the transition instruction were removed.
- Armour Thyroid, NP Thyroid, and similar products are still manufactured, prescribed, and dispensed.
- The FDA has said it supports a first formal approval of a desiccated thyroid extract and planned draft compliance guidance by August 2026.
- A 2026 study of 1.26 million patients associated T3-containing therapy, including NDT, with lower dementia and mortality risk than levothyroxine alone. The data are observational.
- The main current obstacle is coverage. CVS Caremark removed NDT from its standard formulary on April 1, 2026.
This article is educational and is not medical advice. Do not stop, start, or change thyroid medication without your prescriber. Thyroid hormone dosing is individual and requires lab monitoring.
Updated September 2026. This article was first published in August 2025, when the FDA announced it would remove natural desiccated thyroid from the market. That plan was withdrawn on March 11, 2026. Sections below have been rewritten to reflect the current status.
What the FDA Announced in August 2025
Evidence: FDA letters and public statements (primary regulatory documents)
On August 6, 2025, the FDA sent letters to manufacturers, importers, and distributors of animal-derived thyroid products stating that the products are unapproved and could not continue to be marketed without going through the approval process. Patients were encouraged to work with their doctors to move to an FDA-approved medication within roughly 12 months. Had that held, NDT would have left pharmacy shelves by late summer 2026.
NDT is a small share of thyroid prescribing. According to the FDA's own figures, about 1.5 million US patients filled prescriptions for animal-derived thyroid medication in 2024, compared with about 22 million for levothyroxine. Many NDT patients report having tried levothyroxine first.
Why the FDA Moved Against Natural Desiccated Thyroid
Evidence: FDA notice to industry, August 6, 2025; FDA thyroid actions page; citizen petition FDA-2026-P-1307
The FDA gave several reasons in its August 2025 notice to industry. They fall into one regulatory argument and a set of quality arguments.
The regulatory argument: NDT is a biologic without a license
Desiccated thyroid has been sold since the 1890s and predates the 1938 Federal Food, Drug, and Cosmetic Act. No manufacturer ever submitted it for approval, so every NDT product on the market is technically an unapproved drug. For decades the agency tolerated this under enforcement discretion.
What changed is classification. The FDA determined that animal-derived thyroid products contain protein, principally thyroglobulin from the pig gland, and therefore meet the legal definition of a biological product under section 351 of the Public Health Service Act. Biologics can only be marketed with an approved Biologics License Application (BLA). No BLA exists for any NDT product. The classification also removes the compounding exemptions that apply to conventional drugs, so compounding pharmacies can no longer legally prepare desiccated thyroid either.
The quality arguments
The notice listed four concerns tied to the products' animal origin.
- Uncharacterized compounds. Because the tablets are made from ground thyroid tissue, they contain many substances beyond T4 and T3 that have not been characterized for safety or effectiveness under current standards.
- Potency variation. The manufacturing process can produce tablets with inconsistent hormone content, including within the same batch, which the FDA said can leave patients under- or over-treated.
- Impurities and contaminants. The agency named process-related impurities, elemental impurities, and impurities unique to animal thyroid such as organic iodine and inorganic iodide, along with the possibility of microbial contamination from animal tissue.
- Adverse event reports. The FDA stated it had received complaints and adverse event reports related to the safety and strength of these products. It did not publish the reports or their number, and the notice did not cite specific cases of harm from currently marketed brands.
The FDA also pointed to professional society guidelines, which recommend synthetic levothyroxine as the first-line treatment for hypothyroidism.
The objections
The Alliance for Pharmacy Compounding filed a citizen petition in February 2026 challenging the biologic classification. Its argument is that thyroglobulin is an inactive component that breaks down in digestion and plays no therapeutic role, and that the FDA's own policy states a product containing a protein only as an inactive ingredient is not a biological product. The petition also objected that the determination was made through internal interpretation rather than notice-and-comment rulemaking. The FDA had not ruled on the petition as of this update.
On potency, critics noted that variation is not unique to animal-derived products. In June 2025, Accord Healthcare recalled over 82,000 bottles of levothyroxine after testing found subpotent tablets, one of several levothyroxine recalls that year. Another multi-strength levothyroxine recall for subpotency followed in July 2026. The FDA already has authority to act against any manufacturer that fails quality standards, and its March 2026 letter confirmed that manufacturer-level enforcement is the approach it now intends to use.
Levothyroxine vs Natural Desiccated Thyroid
Evidence: prescribing information and clinical guidelines
| Category | Levothyroxine (T4) | Natural Desiccated Thyroid (NDT/DTE) |
|---|---|---|
| What it is | Synthetic T4 only. First-line therapy in professional guidelines. Relies on the body converting T4 to active T3. | Porcine thyroid extract containing both T4 and T3 plus trace thyroid compounds. |
| Common side effects | Mostly dose-related. Too high: palpitations, anxiety, insomnia, heat intolerance. Too low: fatigue, weight gain, cold intolerance, low mood. | Similar dose-related effects. Hyperthyroid-like symptoms can appear near the T3 peak shortly after dosing. |
| Serious risks if overdosed | Atrial fibrillation, bone loss with long-term TSH suppression, strain in existing heart disease. | Same risks if TSH is suppressed. Caution advised with cardiovascular disease and osteoporosis. |
| Strengths | Most studied, consistent potency, wide availability, flexible dosing. | Contains T3 directly. Some patients report better symptom relief, especially poor T4-to-T3 converters. |
| Weaknesses | Some patients stay symptomatic despite normal labs. Repeated subpotency recalls. | Shorter T3 half-life can cause peaks and troughs. Smaller evidence base. Possible batch variability. |
Most reported side effects for either option reflect under- or over-replacement rather than a reaction to the drug itself. Dose adjustments belong with your prescriber.
What the Research Shows
Evidence: one randomized crossover trial, one systematic review, one large observational cohort
Patients who stay on NDT generally do so because they report feeling better on it. Levothyroxine is cheaper, easier to obtain, and more widely covered. The published comparisons give that patient experience partial support.
The 2013 crossover trial
A randomized, double-blind crossover study of 70 hypothyroid patients at Walter Reed compared NDT with levothyroxine, with each patient taking both for 16 weeks. Objective symptom and cognitive scores showed no difference between treatments. Asked which they preferred at the end, 48.6 percent chose NDT and 18.6 percent chose levothyroxine, and the NDT preference group lost a modest amount of weight. A blinded preference gap of that size suggests some patients notice a difference standard labs do not capture.
The 2024 systematic review
A review published in Thyroid examined nine nonrandomized studies, two randomized trials, and three case reports comparing NDT with levothyroxine or combination therapy. The two randomized trials found no difference in quality of life or symptoms, which positions NDT as comparable rather than superior. The nonrandomized studies favored NDT on symptoms and quality of life. The authors rated overall study quality as limited and noted possible increases in heart rate and reductions in HDL with NDT, with conflicting results across studies.
The 2026 dementia and mortality study
A study in the Journal of Clinical Endocrinology and Metabolism analyzed records from 1.26 million hypothyroid patients and 3.32 million controls over 20 years. Patients treated with levothyroxine alone carried a higher risk of dementia and more than double the risk of death compared with controls, even with normal TSH. Patients whose treatment contained T3, either synthetic combination therapy or desiccated thyroid extract, showed lower dementia and mortality risk. This is observational data. It shows association, not cause, and it does not establish that switching therapies changes outcomes. It does raise a question about whether a normal TSH on levothyroxine is a complete measure of treatment success. The senior author, Dr. Antonio Bianco, is a former president of the American Thyroid Association.
Where Things Stand in September 2026
Evidence: FDA letter of March 11, 2026; manufacturer press releases
Public response to the August 2025 announcement was strong. Patient petitions gathered thousands of signatures, thyroid advocacy groups organized, and members of Congress questioned the agency. FDA Commissioner Marty Makary posted that the agency was committed to pursuing the first approval of desiccated thyroid extract and would maintain access in the meantime.
On March 11, 2026, the FDA formalized the change in a new letter to manufacturers, importers, and distributors. Three things changed. The language directing patients to transition to approved medications was removed. The August 2026 removal deadline was replaced with a plan to issue draft guidance on compliance priorities by August 2026. The agency committed to a risk-based enforcement approach, meaning action against individual manufacturers with quality failures rather than against the product category. The FDA also said it intends to issue separate guidance in 2026 on how manufacturers should develop these products for marketing applications.
As of this update the draft compliance guidance had not appeared on the FDA's website. NDT products continue to be manufactured and dispensed under the risk-based policy while it is pending.
The approval pathway is moving. Acella Pharmaceuticals and its affiliate Neuvosyn Laboratories reported positive topline results in September 2025 from a Phase II randomized, double-blind trial of North Star, an investigational desiccated thyroid product they intend to submit for approval as a biologic. Approval would make it the first NDT product with a formal FDA license.
Two cautions. Enforcement discretion is policy rather than law, and a future administration could change it. NDT products also remain technically unapproved until a license is granted, which is what allows the coverage decision described next.
The Current Problem Is Insurance
Evidence: formulary notices; manufacturer access programs
While the FDA softened, at least one pharmacy benefit manager moved the other way. Starting April 1, 2026, CVS Caremark, which manages prescription benefits for a large share of American health plans including some Aetna plans, removed NDT medications from its standard formulary. Patients on affected plans now pay cash or request an exception, even though the medication remains legal.
If your coverage dropped NDT, there are several routes. Your prescriber can file a formulary exception or prior authorization documenting that you did not do well on levothyroxine. AbbVie has offered a coupon program for Armour Thyroid for patients not on government-subsidized plans, and Acella has published access and pricing guidance for NP Thyroid. Cash prices at independent pharmacies and discount programs vary widely, so price each option before assuming the medication is out of reach.
Closing Thoughts
Evidence: author perspective
A medication with a 130-year prescribing history was months away from leaving the market, and the FDA changed course after patients, practitioners, and elected officials objected. The agency's current position, enforcement against quality failures rather than removal of the category, is the standard I would have argued for from the start.
My own mild hypothyroidism improved with dietary changes made under the supervision of my healthcare provider, and Dr. Ray Peat's writing on thyroid-supportive eating shaped that approach. That is one person's experience, not a treatment recommendation. Decisions about thyroid medication belong in a conversation with your prescriber and should be guided by symptoms and labs together.
Frequently Asked Questions
Evidence: summary of sources cited above
Is Armour Thyroid being banned in 2026?
No. The FDA's March 11, 2026 letter removed the removal deadline from its August 2025 announcement. Armour Thyroid, NP Thyroid, and other NDT products remain available by prescription while manufacturers pursue formal approval.
Can I still fill my natural desiccated thyroid prescription?
Yes. NDT remains legal to manufacture, prescribe, and dispense. For some patients the obstacle is insurance coverage rather than availability.
Why did the FDA target natural desiccated thyroid?
NDT products have never gone through formal FDA approval, and the agency cited concerns about safety, purity, and potency tied to their animal origin. The announcement did not cite documented harm from currently marketed products.
Will insurance cover NDT in 2026?
It depends on your plan. CVS Caremark removed NDT from its standard formulary in April 2026. Formulary exceptions, manufacturer coupons, and cash pricing at independent pharmacies are the main workarounds.
Is an FDA-approved natural thyroid medication coming?
Possibly. Neuvosyn Laboratories reported positive Phase II results for North Star in September 2025 and intends to seek approval through the biologics pathway. The FDA has said it supports a first-ever DTE approval.
- FDA. Letter to Manufacturers, Importers, and Distributors of Animal-Derived Thyroid Products. March 11, 2026. fda.gov/media/191621
- FDA. FDA's Actions to Address Unapproved Thyroid Medications. August 2025, revised March 2026. fda.gov
- Beltrão FEL, Carvalhal G, Meneghini V, et al. Treatment of Hypothyroidism That Contains Liothyronine is Associated With Reduced Risk of Dementia and Mortality. J Clin Endocrinol Metab. 2026;111(2):561-571. doi.org/10.1210/clinem/dgaf367
- Hoang TD, Olsen CH, Mai VQ, Clyde PW, Shakir MK. Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized, double-blind, crossover study. J Clin Endocrinol Metab. 2013;98(5):1982-1990. doi.org/10.1210/jc.2012-4107
- Riis KR, Larsen CB, Bonnema SJ. Potential Risks and Benefits of Desiccated Thyroid Extract for the Treatment of Hypothyroidism: A Systematic Review. Thyroid. 2024;34(6):687-701. doi.org/10.1089/thy.2023.0649
- Acella Pharmaceuticals. Press release: Acella Thanks FDA for Maintaining Access to Desiccated Thyroid Extract Products. March 25, 2026.
- Accord Healthcare. Levothyroxine sodium tablets recall notice. June 2025.
- FDA. Notice to Industry: Marketed Unapproved Animal-Derived Thyroid Products. August 6, 2025. fda.gov/media/188081
- Alliance for Pharmacy Compounding. Citizen Petition regarding the classification of desiccated thyroid extract as a biological product. Docket FDA-2026-P-1307. February 4, 2026.
