Adthyza, NP Thyroid, Renthyroid, Armour Thyroid, Niva Thyroid, Thyroid

Medically reviewed by Dena Westphalen, PharmD on May 9, 2023
Written by Amber Watson, PharmD

This article describes Armour Thyroid’s uses, side effects, and more. Below you’ll also find some coupon options to help save on the cost of Armour Thyroid.

Note: The Food and Drug Administration (FDA) has not approved Armour Thyroid. This is because the drug has been available since before the FDA began its drug approval process. If you have questions about this, talk with your doctor or pharmacist.

Boxed warning: Not to be used as a weight loss aid

Armour Thyroid has a boxed warning about not using the drug as a weight loss aid. Boxed warnings are serious warnings about the safety of certain medications.

For details, see the “Interactions and warnings for Armour Thyroid” section below.

Below you’ll find answers to a few commonly asked questions about Armour Thyroid.

Can I switch from other drugs for an underactive thyroid, such as levothyroxine or NP Thyroid, to Armour Thyroid?

Yes, if your doctor advises it, you can switch from Armour Thyroid to another drug for an underactive thyroid.

Armour Thyroid belongs to a group of drugs called thyroid hormones. It contains an active drug called desiccated thyroid. (An active drug is the ingredient that makes a drug work.) Desiccated thyroid is also available as the brand-name drug NP Thyroid.

Other thyroid hormone drugs include levothyroxine (Levoxyl, Synthroid, others) and liothyronine (Cytomel). Your doctor can recommend the thyroid hormone drug that’s best for your condition.

If you’re interested in switching from one thyroid hormone drug to another, talk with your doctor. If they approve a change from one drug to the other, they’ll explain the dosage conversion between these treatments.

Does Armour Thyroid cause long-term side effects?

No, long-term side effects aren’t expected with Armour Thyroid. In the prescribing information* for the drug, specific side effects weren’t reported in people who had taken Armour Thyroid for a long time. Long lasting side effects after treatment ended also weren’t reported.

Talk with your doctor if you have questions about possible long-term side effects with Armour Thyroid.

* It’s important to note that side effects of Armour Thyroid weren’t evaluated in studies. For details about this, see the “Side effects of Armour Thyroid” section below.

How does Armour Thyroid work? And how long does it take to start working?

Armour Thyroid works by replacing thyroid hormones in your body. Your body may not make enough thyroid hormones due to an underactive thyroid, certain thyroid nodules or goiters, or thyroid cancer. 

When taking Armour Thyroid, your thyroid hormones can reach their usual levels. As a result, Armour Thyroid helps ease symptoms of an underactive thyroid. It can also help lower the risk of thyroid nodules, goiters, or thyroid cancer getting worse or returning after treatment. 

It may take 4–6 weeks for your thyroid hormone levels to reach their usual range after starting the drug. Your doctor will give you a blood test to check your thyroid hormone levels. They’ll use the test results to help decide whether Armour Thyroid is working.

Armour Thyroid’s half-life is up to 6 days. Half-life is the time it takes half of a drug’s dose to leave your body. This means it could take up to 6 days for half of a dose of Armour Thyroid to leave your system.

If you have questions about what to expect while taking Armour Thyroid, talk with your doctor.

Is hair loss a side effect of Armour Thyroid?

Hair loss was not reported as a side effect in the prescribing information* for Armour Thyroid. But hair loss can be a symptom of an underactive thyroid, which Armour Thyroid is used to treat.

If you have hair loss or thinning hair while taking Armour Thyroid, talk with your doctor. They can give you a blood test to check your thyroid hormone levels. The test results will help your doctor decide whether Armour Thyroid is working.

If your thyroid hormone levels are not in the usual range, your doctor may adjust your dosage of Armour Thyroid. Doing so may help ease hair loss and other symptoms of an underactive thyroid.  

* It’s important to note that side effects of Armour Thyroid weren’t evaluated in studies. For details about this, see the “Side effects of Armour Thyroid” section below.

How do I know if Armour Thyroid is not working?

Having symptoms of the condition you’re taking Armour Thyroid to treat can be a sign that the drug is not working. 

For example, Armour thyroid can be used to treat an underactive thyroid. If the drug isn’t working for this condition, you may notice weight gain, hair loss, low energy, and depression.

Armour Thyroid can also be used for certain thyroid nodules, goiters, and thyroid cancer. If the drug isn’t working for these conditions, you may notice a hoarse voice, neck pain, neck swelling, and trouble breathing or swallowing.

If you have symptoms of the condition you’re using Armour Thyroid to treat, talk with your doctor. They can give you a blood test to check your thyroid hormone levels. The test results will help your doctor decide whether Armour Thyroid is working.

Armour Thyroid may cause mild or serious side effects. Possible mild and serious side effects of Armour Thyroid are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

Keep in mind that side effects of Armour Thyroid weren’t evaluated in studies. This is because the drug has been available since before the Food and Drug Administration required studies for drug approval. For this reason, detailed information about side effects is not available in the prescribing information for Armour Thyroid. 

To learn more about Armour Thyroid’s side effects, you can ask your doctor or pharmacist.

Mild side effects

A possible mild side effect of Armour Thyroid is below. This article doesn’t include all possible mild side effects of the drug.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

One of Armour Thyroid’s mild side effects is mild allergic reaction. For details about this, see the “Interactions and warnings for Armour Thyroid” section below.

Serious side effects

Serious side effects of Armour Thyroid are listed below.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, Armour Thyroid’s serious side effects include:

• high thyroid hormone levels
• severe allergic reaction*

* For details about this side effect, see the “Interactions and warnings for Armour Thyroid” section below.

The dosage of Armour Thyroid your doctor prescribes may vary based on your condition and certain other factors. Talk with your doctor about the dosage you should follow.

Taking Armour Thyroid

Armour Thyroid comes as a tablet that you swallow. It’s taken without food on an empty stomach. You should take it 30–60 minutes before your first meal of the day.

Your doctor will talk with you about how to take Armour Thyroid. They’ll explain how much to take and how often. Always follow your doctor’s recommendation.

Overdose of Armour Thyroid

You should not take more Armour Thyroid than your doctor prescribes. For some drugs, doing so may lead to serious side effects or overdose.

If you think you’ve taken too much Armour Thyroid, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

You may be able to save money on your prescription for Armour Thyroid by using our Perks discount coupons. They can be found at the end of this article.

If you have questions about how to pay for Armour Thyroid, talk with your doctor or pharmacist.

Note: Optum Perks coupons cannot be used with insurance copays or benefits.

Below, you’ll find information about Armour Thyroid’s possible interactions and warnings.

Interactions of Armour Thyroid

For some medications, certain things may affect how the drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take Armour Thyroid, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:

• prescription drugs
• over-the-counter medications
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for Armour Thyroid” section just below.

Warnings for Armour Thyroid

Armour Thyroid should not be taken in certain situations.

Boxed warning: Not to be used as a weight loss aid

Armour Thyroid has a boxed warning about not using the drug as a weight loss aid. Boxed warnings are serious warnings about the safety of certain medications.

Doctors will not prescribe Armour Thyroid as a weight loss or weight management aid. This is because the large dosages required for weight management may lead to serious and possibly life threatening side effects. Examples include an irregular heartbeat, seizures, and blood clots.

If you’re interested in weight management aids, talk with your doctor. They can recommend options for you.

To learn more about this warning, talk with your doctor or pharmacist.

Other warnings

Armour Thyroid could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether Armour Thyroid is a safe option for you. These warnings may differ based on the form of Armour Thyroid you take.

Ask your doctor about specific warnings for Armour Thyroid, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Armour Thyroid can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to Armour Thyroid or any of its ingredients, your doctor will likely not prescribe Armour Thyroid. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to Armour Thyroid, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Pregnancy or breastfeeding and Armour Thyroid

Information about Armour Thyroid and pregnancy and breastfeeding is described below.

Armour Thyroid and pregnancy

In general, Armour Thyroid is considered safe to take during pregnancy. That said, ask your doctor about whether they feel it’s safe for you.

Armour Thyroid and breastfeeding

It’s not known whether Armour Thyroid should be taken while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication.

Uses for Armour Thyroid are described below.

Note: The Food and Drug Administration (FDA) has not approved Armour Thyroid. This is because the drug has been available since before the FDA began its drug approval process. If you have questions about this, talk with your doctor or pharmacist.

Use for underactive thyroid

Doctors may prescribe Armour Thyroid for treating an underactive thyroid, which is also called hypothyroidism. It’s used for this purpose in adults and children. The drug is usually prescribed as a long-term treatment.

With an underactive thyroid gland, your body doesn’t make enough thyroid hormones. Having an underactive thyroid can cause many functions in your body to slow down. Symptoms can include weight gain, hair loss, low energy, and depression.

Armour Thyroid is prescribed together with corticosteroids for a type of underactive thyroid called myxedema.

Doctors may not prescribe Armour Thyroid in certain situations, such as for use as a weight loss aid. In fact, Armour Thyroid has a boxed warning about not using the drug for this purpose. Boxed warnings are serious warnings about the safety of certain medications. For more details, see the “Interactions and warnings for Armour Thyroid” section above.

Use for other thyroid conditions

Doctors may prescribe Armour Thyroid for thyroid conditions, including certain thyroid nodules, goiters, and thyroid cancer. It’s used for these purposes in adults and children. The drug is usually prescribed as a long-term treatment.

With thyroid nodules and goiters, you have lumps of cells in your thyroid gland. These conditions may cause your thyroid to appear larger than usual. Symptoms of thyroid nodules and goiters include having a hoarse voice, neck pain, and trouble breathing or swallowing.

With thyroid cancer, cancer cells grow in your thyroid gland and may spread to other parts of your body. Symptoms of thyroid cancer include having a hoarse voice and pain, swelling, or nodules in your neck.

Armour Thyroid is prescribed together with radioactive iodine for thyroid cancer.

Doctors may not prescribe Armour Thyroid in certain situations, such as for use as a weight loss aid. In fact, Armour Thyroid has a boxed warning about not using the drug for this purpose. Boxed warnings are serious warnings about the safety of certain medications. For more details, see the “Interactions and warnings for Armour Thyroid” section above.

This article describes Armour Thyroid’s uses and dosage, ways to save on cost, and more. Let your doctor know if you have questions about Armour Thyroid or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• Do I have any health conditions that interact with Armour Thyroid?
• What side effects should I expect while taking Armour Thyroid?
• Will I take Armour Thyroid along with other treatments for my condition?

• Armour Thyroid – thyroid, porcine tablet. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/227e445c-b03d-44a3-b911-f00d3b2e118f/spl-doc

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.