Home Ingredients Porcine Thyroid Glandular (Desiccated Thyroid)
Thyroid Health

Porcine Thyroid Glandular (Desiccated Thyroid)

Sus scrofa
Evidence Level
Limited
2 Clinical Trials
4 Documented Benefits
2/5 Evidence Score

Porcine "desiccated thyroid" is dried, powdered pig thyroid gland, but the name covers two very different products. PRESCRIPTION desiccated thyroid extract (Armour Thyroid, NP Thyroid) is an FDA-regulated drug standardized to contain thyroxine (T4) and triiodothyronine (T3), used by clinicians to treat diagnosed hypothyroidism. OTC "thyroid glandular" or "raw thyroid" capsules are sold as dietary supplements and are legally required to be depleted of thyroid hormone, yet independent testing has repeatedly found active T4/T3 in them. The supplement versions have no controlled-trial support for improving thyroid function and carry a real risk of delivering undisclosed hormone.

Studied Dose Prescription DTE is dosed and monitored by a clinician (e.g., 1 grain = 65 mg, titrated to TSH). OTC glandulars have no established safe self-dose and are not recommended without medical supervision.
Active Compound Porcine thyroid tissue (thyroglobulin matrix). Prescription extract is standardized to about 38 mcg T4 plus 9 mcg T3 per 65 mg (1 grain). OTC glandulars: variable, often-undisclosed residual T4/T3.

Benefits

Thyroid hormone replacement (prescription form only)

Standardized prescription porcine desiccated thyroid supplies both T4 and T3 and can treat diagnosed hypothyroidism under medical care. This is a regulated drug effect, not a property of over-the-counter glandular supplements.

Supported by Trial 1, Trial 2

Combined T4 + T3 delivery

Because pig thyroid contains T3 as well as T4, desiccated thyroid delivers both hormones in a fixed ratio. Some patients report feeling better on it, though controlled trials have not shown it outperforms standard levothyroxine on objective measures.

Supported by Trial 1

Patient preference in some individuals

In a randomized crossover trial of treated hypothyroid patients, a substantial minority preferred desiccated thyroid over levothyroxine, but it did not improve cognition or quality-of-life endpoints. Preference is not the same as a superior outcome.

Supported by Trial 1

Marketed for general "thyroid support" (unproven)

OTC glandulars are promoted for energy, metabolism, and thyroid support. There is no controlled evidence that hormone-free glandular tissue improves thyroid function, and any perceived benefit may come from undisclosed hormone contamination.

Supported by Trial 2, Trial 1

Mechanism of action

1

Preformed thyroid hormone

Prescription (and hormone-contaminated OTC) desiccated thyroid acts by supplying preformed T4 and T3, which bind nuclear thyroid hormone receptors and regulate metabolic rate, the same mechanism as pharmaceutical thyroid hormone.

2

Fixed T4:T3 ratio from animal tissue

Pig thyroid provides a higher proportion of T3 relative to T4 than the human thyroid secretes, which can produce supraphysiologic T3 peaks after dosing compared with T4-only levothyroxine.

3

Glandular "tissue therapy" theory (unsupported)

Marketing of hormone-depleted glandulars rests on an unproven idea that consuming animal thyroid tissue nourishes the human thyroid. No credible evidence supports oral glandular tissue improving thyroid function once hormone is removed.

Clinical trials

1
Desiccated Thyroid vs Levothyroxine (Crossover RCT)

Randomized, double-blind, crossover trial; 70 hypothyroid patients; 16 weeks per arm (Hoang 2013).

Adults with primary hypothyroidism on stable hormone replacement.

Prescription porcine desiccated thyroid was safe and caused modest weight loss; about 49% of patients preferred it. However, it did NOT improve neurocognitive function or most quality-of-life measures versus levothyroxine. Applies to the standardized prescription drug, not OTC glandulars.

2
Hormone Content of OTC Thyroid Supplements

Laboratory analysis of commercially available thyroid health supplements (Kang 2013).

Over-the-counter thyroid support products (not patients).

9 of 10 tested supplements contained detectable triiodothyronine (T3) and/or thyroxine (T4), some at clinically relevant amounts, despite being sold as dietary supplements that should be hormone-free. Demonstrates the contamination risk of glandular products.

Side effects and drug interactions

Common Potential side effects

Symptoms of thyroid hormone excess (palpitations, rapid heartbeat, anxiety, tremor, sweating, heat intolerance, unintended weight loss), especially from hormone-contaminated OTC products.
Atrial fibrillation and other cardiac arrhythmias with over-replacement, particularly in older adults.
Accelerated bone loss and osteoporosis risk with chronic excess thyroid hormone.
Unpredictable, batch-to-batch variation in active hormone content of OTC glandulars makes dosing unreliable.
Can mask or destabilize an underlying thyroid disorder and confound diagnosis if taken without testing.

Important Drug interactions

Levothyroxine / liothyronine and other thyroid medications: additive effect that can cause iatrogenic thyrotoxicosis. Do not combine without medical supervision.
Warfarin and other anticoagulants: increased thyroid hormone enhances anticoagulant effect and bleeding risk.
Antidiabetic drugs (insulin, oral agents): thyroid hormone changes can raise blood glucose and alter insulin requirements.
Beta-blockers: may blunt the cardiac warning signs of hormone excess, masking over-replacement.

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Frequently asked questions about Porcine Thyroid Glandular (Desiccated Thyroid)

What is the recommended dosage of Porcine Thyroid Glandular (Desiccated Thyroid)?

The clinically studied dose for Porcine Thyroid Glandular (Desiccated Thyroid) is Prescription DTE is dosed and monitored by a clinician (e.g., 1 grain = 65 mg, titrated to TSH). OTC glandulars have no established safe self-dose and are not recommended without medical supervision.. Always follow product labeling and consult a healthcare provider for personalized dosing recommendations.

What is Porcine Thyroid Glandular (Desiccated Thyroid) used for?

Porcine Thyroid Glandular (Desiccated Thyroid) is studied for thyroid hormone replacement (prescription form only), combined t4 + t3 delivery, patient preference in some individuals. Standardized prescription porcine desiccated thyroid supplies both T4 and T3 and can treat diagnosed hypothyroidism under medical care. This is a regulated drug effect, not a property of over-the-counter glandular supplements.

Are there side effects from taking Porcine Thyroid Glandular (Desiccated Thyroid)?

Reported potential side effects may include: Symptoms of thyroid hormone excess (palpitations, rapid heartbeat, anxiety, tremor, sweating, heat intolerance, unintended weight loss), especially from hormone-contaminated OTC products. Atrial fibrillation and other cardiac arrhythmias with over-replacement, particularly in older adults. Always consult a healthcare provider before starting any new supplement, especially if you have underlying conditions or take medications.

Does Porcine Thyroid Glandular (Desiccated Thyroid) interact with medications?

Known drug interactions may include: Levothyroxine / liothyronine and other thyroid medications: additive effect that can cause iatrogenic thyrotoxicosis. Do not combine without medical supervision. Warfarin and other anticoagulants: increased thyroid hormone enhances anticoagulant effect and bleeding risk. Consult a pharmacist or healthcare provider if you take prescription medications.

Is Porcine Thyroid Glandular (Desiccated Thyroid) good for thyroid health?

Yes, Porcine Thyroid Glandular (Desiccated Thyroid) is researched for Thyroid Health support. Standardized prescription porcine desiccated thyroid supplies both T4 and T3 and can treat diagnosed hypothyroidism under medical care. This is a regulated drug effect, not a property of over-the-counter glandular supplements.

References(4 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Hoang TD, Olsen CH, Mai VQ, Clyde PW, Shakir MK. Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized, double-blind, crossover study. J Clin Endocrinol Metab. 2013;98(5):1982-90. doi: 10.1210/jc.2012-4107.PubMedUsed to support: Supports the prescription desiccated-thyroid context: in a double-blind crossover RCT, porcine DTE was a safe alternative to levothyroxine and about 49% of patients preferred it, but it did NOT improve the primary neurocognitive or quality-of-life outcomes. Applies to the standardized prescription drug, not OTC glandular supplements.
  2. Kang GY, Parks JR, Fileta B, Chang A, Abdel-Rahim MM, Burch HB, Bernet VJ. Thyroxine and triiodothyronine content in commercially available thyroid health supplements. Thyroid. 2013;23(10):1233-7. doi: 10.1089/thy.2013.0101.PubMedUsed to support: Basis for the contamination caution: 9 of 10 over-the-counter thyroid health supplements contained detectable T3 and/or T4, showing that glandular products can deliver undisclosed, unpredictable thyroid hormone.
  3. Jonklaas J, Bianco AC, Bauer AJ, Burman KD, Cappola AR, Celi FS, et al. Guidelines for the treatment of hypothyroidism: prepared by the American Thyroid Association task force on thyroid hormone replacement. Thyroid. 2014;24(12):1670-751. doi: 10.1089/thy.2014.0028.PubMedUsed to support: Authoritative guidance: the American Thyroid Association does not recommend desiccated thyroid extract as routine first-line therapy for hypothyroidism, citing the absence of long-term safety and superiority data.
  4. Hoang TD, Mai VQ, Clyde PW, Shakir MK. Over-the-counter-drug-induced thyroid disorders. Endocr Pract. 2013;19(2):268-74. doi: 10.4158/EP12298.OR.PubMedUsed to support: Documents that over-the-counter products, including thyroid glandulars, can cause thyroid dysfunction, including iatrogenic thyrotoxicosis, underscoring why these require medical supervision.