Armour Thyroid vs. Unithroid

See how Armour Thyroid and Unithroid compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Armour Thyroid combines natural T4 and T3 hormone from pork thyroid gland, while Unithroid is a synthetic, T4-only tablet.

  • Both treat hypothyroidism with lifelong daily dosing, but only Armour Thyroid is FDA-approved to suppress TSH in benign thyroid nodules and goiter.

  • Unithroid went through full modern FDA approval with standardized dosing, while Armour Thyroid is an older grandfathered product with more variable hormone content.

Armour Thyroid vs. Unithroid Drug Summary

Armour Thyroid

Armour Thyroid is a natural desiccated thyroid hormone replacement made from porcine thyroid gland, containing both T4 and T3. It treats hypothyroidism and suppresses pituitary TSH in certain thyroid conditions, taken once daily by mouth.

Unithroid

Unithroid is a synthetic levothyroxine (T4) tablet used to replace thyroid hormone in hypothyroidism and to suppress TSH after thyroid cancer surgery. It's taken once daily by mouth, on an empty stomach before breakfast.

Armour Thyroid vs. Unithroid Side Effects

Armour Thyroid

Most common
Tremors (unspecified rate)
Palpitations (unspecified rate)
Nervousness (unspecified rate)
Headache (unspecified rate)

Unithroid

Most common
Tremors (unspecified rate)
Palpitations (unspecified rate)
Nervousness (unspecified rate)
Headache (unspecified rate)

Armour Thyroid vs. Unithroid Dosage

Armour Thyroid

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 15 mg once daily At the start
Maximum dose 60-120 mg once daily If needed
Dose changes 3 increases As tolerated

Unithroid

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 12.5-25 mcg once daily At the start
Maximum dose 100-200 mcg once daily If needed
Dose changes 2 increases As tolerated

Armour Thyroid vs. Unithroid Indications

Armour Thyroid

Armour Thyroid is FDA-recognized for replacing thyroid hormone in primary, secondary, and tertiary hypothyroidism. It's also approved to suppress pituitary TSH in thyroid nodules, Hashimoto's thyroiditis, multinodular goiter, and thyroid cancer.

  • Primary, secondary, or tertiary hypothyroidism replacement

  • TSH suppression in thyroid nodules and goiter

  • TSH suppression in Hashimoto's thyroiditis

  • Adjunct TSH suppression in thyroid cancer

Unithroid

Unithroid replaces thyroid hormone in primary, secondary, and tertiary hypothyroidism in both children and adults. It's also approved as an adjunct to surgery and radioiodine therapy for TSH suppression in certain thyroid cancers, but not for benign nodules or goiters.

  • Primary, secondary, or tertiary hypothyroidism replacement

  • Approved for pediatric and adult patients

  • Adjunct TSH suppression in thyroid cancer only

  • Not approved for benign nodules or goiter suppression

Armour Thyroid vs. Unithroid Pros and Cons

Armour Thyroid

Armour Thyroid offers combination T4/T3 therapy from natural desiccated thyroid extract, appealing to patients who don't feel well on T4-only drugs. Because it predates modern FDA drug approval requirements, it hasn't undergone the same large-scale efficacy trials as newer synthetic options.

Pros

  • Contains both T4 and T3, not just T4

  • Approved for TSH suppression in nodules and goiter

  • Naturally sourced from desiccated porcine thyroid

Cons

  • Not reviewed through the modern FDA approval process

  • Hormone content can vary from batch to batch

  • Frequently affected by manufacturing shortages

Unithroid

Unithroid is a synthetic, T4-only levothyroxine that went through full FDA approval in 2001, giving it a more standardized safety and efficacy record. It comes in twelve precise dosage strengths, which helps clinicians fine-tune treatment, but it isn't approved for suppressing benign thyroid nodules or goiters.

Pros

  • FDA-approved through the modern NDA process

  • Consistent, standardized synthetic hormone content

  • Twelve dosage strengths allow precise titration

Cons

  • Contains only T4, no added T3 hormone

  • Not approved for suppressing benign nodules or goiter

  • May not relieve symptoms needing extra T3

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