The Food and Drug Administration (FDA) sparked controversy this week with a series of statements about unapproved thyroid medications derived from animal tissue, reflecting tensions over natural drug use in the “Make America Healthy Again” movement.
Last Thursday, the agency issued a statement expressing concerns about the safety and effectiveness of these medications, citing patient complaints and reports of adverse events. The FDA said it had notified manufacturers of its “intent to take action” against the products but would delay enforcement to give patients time to transition to alternative therapies.
“The agency urges patients taking these unapproved animal-derived thyroid medications to treat hypothyroidism to talk to their doctor,” the statement read.
Warnings about unapproved drugs are routine for the FDA, but social media backlash quickly followed, challenging the agency’s stance.
On Wednesday evening, FDA Commissioner Dr. Marty Makary signaled a reversal, posting on X that the FDA was committed to pursuing approval for desiccated thyroid extract once ongoing clinical trials conclude. “In the meantime, we will ensure access for all Americans,” he wrote. Health Secretary Robert F. Kennedy Jr. endorsed the approach, praising Makary’s “gold standard science and common sense.”
Animal-Derived Thyroid Pills
The thyroid gland regulates energy by producing hormones. Hypothyroidism, a condition marked by insufficient hormone production, can cause fatigue, weight gain, depression, menstrual changes, and heightened cold sensitivity. Standard treatment involves synthetic hormone replacement therapy, such as levothyroxine or liothyronine, or a combination of both.
Some patients turn to animal-derived thyroid pills—made from dried pig thyroids and sold under brand names including Armour Thyroid, NP Thyroid, Nature-Thyroid, and Natural Thyroid—either due to inadequate response to synthetic drugs or preference for “natural” products. The FDA estimates that roughly 1.5 million Americans were prescribed these products in 2024.
The initial FDA warning highlighted potential risks, including inconsistent hormone levels and contamination, which could lead to ineffective treatment or serious side effects.
Public Reaction
Patients and practitioners reacted swiftly on social media. Functional medicine doctor Will Cole warned that a ban would harm those unresponsive to synthetic medications. Dave Asprey, founder of Bulletproof Coffee, cited his personal success with natural thyroid extract, and Dr. Robert Malone, a controversial figure appointed by Kennedy to a vaccine advisory panel, called the FDA’s warning “terrible news.”
HHS spokesperson Andrew Nixon declined to confirm whether Makary’s reversal was influenced by public feedback but referred media inquiries to the FDA’s previous statement, which emphasized no immediate enforcement and ongoing monitoring of clinical trials.
Safety Concerns and Clinical Perspectives
Endocrinologists stress that FDA-approved synthetic thyroid medications offer regulated dosing, while animal-derived pills carry inconsistent hormone levels, raising risks of heart, bone, and mood complications. Dr. Pieter Cohen of Harvard noted the dangers of over- or underdosing, while Dr. Michael Weintraub of NYU Langone highlighted potential heart rhythm disturbances and osteoporosis from animal-derived products.
Dr. Susan Spratt of Duke Health, however, cautioned against removing the longstanding animal-derived medications without clear evidence of harm, noting that they provide an option for patients who do not respond well to synthetic treatments.
Weintraub added that combining T4 and T3 therapy remains a more precise and safer alternative than animal-derived thyroid pills for most patients.
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