FDA

FDA moves to address unapproved animal-derived thyroid medications

August 12, 2025

FDA has issued letters to manufacturers, importers, and distributors of unapproved animal-derived thyroid medications such as Armour Thyroid, NP Thyroid, and Nature-Throid, alerting them to forthcoming enforcement actions. These desiccated thyroid extract (DTE) products, derived from porcine thyroid glands, haven't undergone FDA review for safety, purity, or potency. Despite being prescribed to approximately 1.5 million patients in 2024, these medications pose risks due to inconsistent dosing and potential impurities, which may lead to adverse health outcomes. In contrast, synthetic levothyroxine and liothyronine products, which are FDA-approved, remain the recommended standard of care for hypothyroidism.

To minimize patient disruption, FDA isn't taking immediate enforcement action, allowing time for clinicians to transition patients to approved therapies. HCPs are encouraged to proactively contact patients using unapproved DTE products and guide them toward FDA-approved alternatives. FDA emphasizes that these unapproved products aren't eligible for compounding and advises patients to consult their physicians for safe treatment adjustments. Professional societies such as the Endocrine Society, ATA, and AACE offer resources to support this transition.

Source:

(2025, August 7). FDA. FDA’s Actions to Address Unapproved Thyroid Medications https://www.fda.gov/drugs/enforcement-activities-fda/fdas-actions-address-unapproved-thyroid-medications