Also known as: Natural Desiccated Thyroid, NP Thyroid
Half-life
48 h
Typical timing
morning
Food rule
empty stomach
Default unit
mg
Overview
Natural Desiccated Thyroid (NDT), commonly known by brand names such as Armour Thyroid and NP Thyroid, is a medication derived from porcine (pig) thyroid glands. It contains a combination of levothyroxine (T4) and liothyronine (T3), along with other thyroid-related compounds like calcitonin and iodine, though the primary active ingredients are T4 and T3. NDT has been used for the treatment of hypothyroidism for over a century. Hypothyroidism is a condition where the thyroid gland does not produce enough thyroid hormones, leading to symptoms such as fatigue, weight gain, constipation, and cold intolerance. NDT works by supplementing the body's natural thyroid hormone supply. Unlike synthetic thyroid hormone preparations which often contain only T4 (like levothyroxine), NDT provides both T4 and T3 in proportions naturally found in a healthy human thyroid, though the exact ratio may vary depending on the sourcing and processing of the porcine glands. The use of NDT persists despite the availability of synthetic T4, with some patients and clinicians reporting perceived benefits, particularly for those who do not feel well on T4-only treatment. (DrugBank, Mayo Clinic)
Deep dive
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Known interactions
Category rule: supplement × medication
Note
Some supplements change how the body processes medications (absorption, liver enzymes, or additive effects).
Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist.
Category rule: vitamin × medication
Note
Certain vitamins interact with specific medications (e.g., vitamin K with blood thinners).
Specific pairs are checked against a licensed source; confirm with your provider.
Sources referenced
* DrugBank
* Mayo Clinic
* FDA label (Armour Thyroid)
* Cochrane Review
* American Association of Clinical Endocrinologists (AACE) guidelines
Stackwise compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician.
Related compounds
Others in the medication category or studied for the same goals.
