Armour Thyroid, or desiccated thyroid extract (DTE), cannot be purchased over the counter. You need a prescription from a doctor to take Armour Thyroid. It is used to treat low thyroid hormone in the body, but it is not considered the standard treatment.

Like any drug containing DTE, Armour Thyroid has not been approved by the U.S. Food and Drug Administration (FDA), due to a lack of evidence that it is safe and effective for the treatment of hypothyroidism.

All new drugs must now have extensive evidence of safety and efficacy and be approved by the FDA before they can become commercially available. However, drugs containing DTE have been prescribed for decades, long before these regulatory processes were established, which is why a doctor can still prescribe Armour Thyroid, despite it being an unapproved drug.

Synthetic forms of thyroid hormones, such as Levoxyl, contain hormones identical to those produced by the human body and are FDA-approved for the treatment of hypothyroidism. These FDA-approved synthetic options offer more consistent, standardized doses than Armour Thyroid and other DTE-containing drugs, and they have well-established evidence of safety and efficacy.

While Armour Thyroid is only available in prescription form, numerous dietary supplements are available over the counter that may claim to be similar and be labeled for “thyroid support” or other uses. However, these supplements are unregulated. Over-the-counter options may contain uncertain amounts of thyroid hormones, potentially causing thyrotoxicosis (dangerously high levels of thyroid hormones) and other adverse health effects.