Natural Desiccated Thyroid • FDA Approved

Armour Thyroid: Natural Desiccated Thyroid

By , HighPeptides Editor

Last updated: March 2026

Porcine thyroid gland extract. Contains T4 + T3 + T2 + T1 + calcitonin. Some patients strongly prefer it over synthetic T4 alone. Used since the 1890s.

0
Typical Dose
(1–2 grains)
T4
Contains Both
T4 + T3
0
First Use
Decade
📋 On this page
  1. What Is Armour Thyroid?
  2. What the Research Shows
  3. NDT vs Synthetic T4
  4. Dosing
  5. Key Takeaways
  6. 🛒 Recommended Products
  7. Related Resources
Background

What Is Armour Thyroid?

Natural desiccated thyroid (NDT) is dried porcine thyroid gland. Unlike synthetic levothyroxine (T4 only), NDT contains multiple thyroid hormones in their natural proportions.

🐷
Complete Hormone Profile

Contains T4, T3, T2, T1, and calcitonin. The T4:T3 ratio is approximately 4:1 by weight, closer to human thyroid secretion than T4 alone.

⚡
Active T3 Included

Unlike levothyroxine, NDT provides direct T3. This may explain why some patients feel more energy and better mood on NDT — no reliance on conversion.

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Long History

NDT was the only thyroid treatment from the 1890s until synthetic T4 was developed in the 1950s. Armour Thyroid (from Forest Pharmaceuticals) is the best-known brand.

🏛️
ATA Position

The American Thyroid Association doesn't recommend NDT as first-line. They cite variable hormone batch content and lack of consistent superiority over levothyroxine.

Research

What the Research Shows

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Context: Studies comparing NDT to levothyroxine show mixed results. Some patients strongly prefer NDT, but objective measures (TSH, thyroid function) often show similar outcomes. The debate continues.

Patient Preference (Surveys)
Significant portion of NDT users prefer it to synthetic T4
30-50%
Objective Improvement (Studies)
Similar TSH normalization and thyroid markers vs levothyroxine
Similar
ATA Recommendation
First-line therapy — levothyroxine (not NDT)
No NDT
Comparison

NDT vs Synthetic T4

Natural Desiccated (Armour)
  • Contains T4 + T3 + T2 + T1
  • Animal-derived (porcine)
  • 4:1 T4:T3 ratio
  • Variable between batches (theoretically)
  • Some patients prefer
  • ~120 years of use
Synthetic Levothyroxine
  • T4 only (prohormone)
  • Synthetic (identical to human)
  • No T3
  • Consistent potency
  • Standard of care
  • Since 1950s
Protocol

Dosing

🌾
Dosing in Grains
  • 1 grain (60mg) = 38mcg T4 + 9mcg T3
  • Start: 30-60mg (½-1 grain)
  • Typical: 60-120mg (1-2 grains)
  • Some go to 90-120mg (1.5-2 grains)
  • Titrate by symptoms + TSH
⏰
Timing
  • Take on empty stomach
  • Divide dose if needed (T3 component)
  • Some split AM/PM for stability
  • Monitor TSH after changes
Bottom Line

Key Takeaways

✅ What We Know
  • FDA-approved medication (grandfathered in)
  • Contains both T4 and T3
  • Some patients strongly prefer it
  • Long history of use since 1890s
  • Works well for many patients
⚠️ What We Don't Know
  • ATA doesn't recommend as first-line
  • Batch-to-batch variability (theoretical)
  • Why some patients respond better
  • Optimal patient selection criteria

Support for thyroid therapy.

🔬 SeleniumThyroid conversion support☀️ Vitamin D3General thyroid health🔩 IronOften needed with thyroid
💊
T4 (Levothyroxine)
Standard synthetic option
→⚡
T3 (Liothyronine)
Active hormone only
→
📚

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⚠️ Disclaimer

Armour Thyroid is a prescription medication. Monitor with regular TSH and Free T3 testing. Not recommended as first-line by ATA guidelines. Many patients do well on it — discuss with your doctor. This is not medical advice. FDA Approved Rx Required