Desiccated Thyroid Extract: what patients and pharmacists need to know
For more than a century, desiccated thyroid extract – commonly known as DTE – has been a trusted treatment for hypothyroidism. Derived from porcine (pig) thyroid glands, DTE contains both thyroxine (T4) and triiodothyronine (T3), the same hormones your thyroid naturally produces.
But DTE is more than just a treatment option. When your thyroid doesn't produce enough hormone on its own, what you're prescribed can affect everything – your energy, your mood, your weight, your ability to think clearly. Getting it right matters, and for millions of Americans, getting it right has meant having access to more than one path.
Today, that access is threatened.
A treatment that has worked for generations
Porcine (pig) thyroid has been used successfully as a treatment for hypothyroidism since the late 1800s. Also known as Desiccated Thyroid Extract (DTE) or Natural Desiccated Thyroid (NDT), these products contain both thyroxine (T4) and triiodothyronine (T3) and are still widely used today. As the name suggests, it is derived from pig thyroid glands and is therefore considered to be a natural thyroid replacement. Synthetic thyroxine and triiodothyronine were both developed in the 1950s and are manufactured in a lab from non-natural sources.
Millions of patients in the United States require thyroid replacement, and many others have subclinical hypothyroidism and may benefit from thyroid supplementation. As with most other types of medications, one therapeutic path is not optimal for everyone. Some patients have better clinical results with porcine thyroid and others need the synthetic thyroid products, which is why keeping all possible avenues available is essential to patients and their providers.
What the FDA changed – and why it matters
In August 2025, the FDA announced a shift in their policy regarding DTE, reclassifying porcine thyroid products as “biologics” instead of “drug products” This shift meant DTE could no longer be compounded in a traditional pharmacy environment, with the FDA also expressing concerns about batch-to-batch dosing consistency in naturally derived products.
However, it’s important to note that porcine thyroid products are already considered "unapproved" – their existence predates the Federal Food, Drug, and Cosmetic Act of 1938. The FDA has given patients and providers a 12-month window to transition away from DTE.
The problem is that the science behind the reclassification doesn't hold up. Here's why:
- The FDA's rationale hinges on thyroglobulin, a protein found in pig thyroid glands – but thyroglobulin is an inactive ingredient. It's broken down in the stomach and plays no therapeutic role in treating hypothyroidism.
- The active ingredients in DTE are levothyroxine (T4) and liothyronine (T3) – well-studied small molecules with decades of documented clinical use, not biologics.
- The FDA's own guidance contradicts this move. The agency's policy states that a drug product containing a protein only as an inactive ingredient is not considered a biological product.
- No formal process was followed. The agency made this change without rulemaking and without a public comment period.
The consequences are real. Biologics face a far more expensive approval pathway with no true generics – only costly "biosimilars." Up to 1.9 million patients could lose access to DTE, and those who remain face significantly higher costs.
What patients who rely on DTE should know
You may be asking yourself: I'm doing well on my natural thyroid replacement – it's been available since the late 1800s. Why is this an issue now?
It's exactly the right question. Not every patient responds adequately to synthetic T4 and T3 preparations. For those patients, DTE isn't a preference, it can be a clinical necessity. Losing access can mean a return to debilitating symptoms, or being left without an effective alternative.
If DTE is part of your treatment plan, now is the time to talk with your prescriber and your pharmacist. Make sure your clinical history with DTE is documented and that your care plan accounts for what may be coming. And if DTE has made a meaningful difference in your health, consider sharing that story – patient voices carry real weight in efforts like this.
A note for pharmacists: how to help your patients
Compounding pharmacists are often the most accessible point of contact for patients managing chronic conditions like hypothyroidism. If you dispense or compound DTE, you're in a unique position to help.
Start with awareness. Many patients won't know about this policy change until it directly affects them. A brief conversation at pickup or during a medication review can make a real difference. You can also help patients document their clinical history with DTE: why synthetic alternatives weren't adequate, what improvement they've experienced, and what losing access would mean. That documentation supports both continuity of care and ongoing advocacy efforts.
Patient-facing materials, including sample emails to Congress and printable bag stuffers, are available at Compounding.com/thyroid.
By Kim Hansen, RPh, FAPC