7 Armour Thyroid Side Effects and How to Manage Them

Armour Thyroid (desiccated thyroid) is an older thyroid medication that’s been used for over a century for hypothyroidism (underactive thyroid). Some people may prefer it over standard treatments since it’s often seen as a more natural option. But it’s not FDA approved. And it carries some extra risks, such as the potential for inconsistent doses and allergic reactions.

Because it contains both T4 and the more active thyroid hormone T3, Armour Thyroid may lead to more ups and downs in your hormone levels. This can increase the chances of side effects — especially if your dose isn’t quite right. Understanding Armour Thyroid side effects can help you get the most from treatment while staying safe.

Armour Thyroid side effects list

Most Armour Thyroid side effects occur when the dose is too high, leading to excess thyroid hormone. This results in symptoms that look like those of hyperthyroidism (overactive thyroid). Even small dose changes can make a big difference. So routine monitoring is key to managing your treatment.

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Common and/or mild Armour Thyroid side effects include:

• Nervousness or irritability

• Heat intolerance

• Excessive sweating

• Appetite changes

• Weight loss

• Trouble sleeping

• Increased heart rate

• Hair loss

Less common but potentially serious Armour Thyroid side effects include:

• Heart palpitations

• Chest pain

• Shortness of breath

• Loss of bone mass and bone fractures

Tell your prescriber if you experience any new, persistent, or worsening side effects. They may order blood tests to check your thyroid hormone levels and adjust your dose if needed. Don’t adjust your dose on your own. Even if you’re feeling off, don’t change your medication regimen without talking to your prescriber.

Below, we’ll go into more detail about seven Armour Thyroid side effects.

1. Nervousness and irritability

Mood changes, such as feeling more nervous or irritable, are possible with Armour Thyroid. This is because thyroid hormones affect chemicals in the brain that play a role in mood and emotion. 

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If you’re feeling unusually anxious or on edge, it can help to try supportive strategies. Add stress-reducing activities, such as controlled breathing, meditation, or yoga, into your routine. Regular exercise, a balanced diet, and good sleep habits can also help improve your mood.

It’s also a good idea to discuss your mental health status with your prescriber before starting treatment. Let them know if you have a history of anxiety or mood disorders. Sometimes, these conditions overlap with thyroid imbalances and may also need treatment.

2. Sweating and heat intolerance

Excessive sweating and heat intolerance are possible with Armour Thyroid. Higher thyroid hormone levels can activate your body’s fight-or-flight response and increase your core body temperature. You might notice sweat on your palms or soles, or all over your body, even in cooler temperatures.

A little extra sweating or warmth can be normal when starting treatment with Armour Thyroid or adjusting your dose. Here are a few tips to help manage it:

• Stay cool. Wear breathable fabrics and be around fans or air conditioning when possible.

• Hydrate. Drink plenty of water throughout the day.

• Use antiperspirants. Clinical-strength options can help keep you dry.

• Track your symptoms. Keep a log and share it with your prescriber if things don’t improve.

If your symptoms are persistent or severe, it could mean you’re getting too much thyroid hormone. In this case, your prescriber may want to check your thyroid hormone levels and adjust your dose if needed.

3. Weight loss or appetite changes

Taking Armour Thyroid may lead to noticeable changes in body weight or appetite. Thyroid hormones help regulate your metabolism — meaning, how your body uses energy. When levels of these hormones are too high, they can cause unintended weight loss or increased appetite, even if your eating habits haven’t changed.

Keep in mind that Armour Thyroid isn’t a weight-loss medication. Some small studies suggest thyroid hormones may influence weight loss, but this isn’t the goal of treatment. The primary goal is to restore and maintain normal thyroid levels.

Talk to your healthcare team if you have unexplained weight loss or appetite changes while taking Armour Thyroid. They may want to check your thyroid hormone levels or watch your weight more closely.

4. Sleep problems

Difficulty falling or staying asleep can be a side effect of Armour Thyroid, especially if your thyroid hormone levels are too high. This is because thyroid hormones affect your sleep. When levels are elevated, your body may feel more alert than it should at night. This can lead to restlessness or poor-quality sleep.

You may notice that you feel less tired or more energized after starting treatment with Armour Thyroid or increasing your dose. You should be able to sleep on a regular schedule as your body gets used to the medication. In the meantime, here are a few tips to improve your sleep hygiene and help you rest better:

• Be consistent about when you go to sleep and wake up, even on weekends.

• Avoid caffeine and alcohol, especially in the late afternoon or evening.

• Keep any naps short and take them earlier in the day.

• Exercise in the morning or early afternoon.

• Turn off screens (e.g., phones, TVs, and tablets) at least an hour before bedtime.

If you have ongoing sleep issues, it could mean your dose is too high. Talk to your prescriber if this is the case.

5. Heart palpitations and increased heart rate

Heart palpitations and a faster heart rate are possible Armour Thyroid side effects. These side effects can happen because thyroid hormones affect your heart, with elevated levels speeding up your heart rate.

Small changes in your heart rate might go unnoticed. But more noticeable symptoms, such as a racing heartbeat, pounding in your chest, or skipped beats, shouldn’t be ignored. Tell your healthcare team right away if these symptoms occur. Seek emergency care if you have severe symptoms, especially if they’re accompanied by chest pain or shortness of breath.

You may not be able to change the effects of thyroid hormones on your heart. But taking steps to improve your heart health can reduce your risk of serious problems. Examples include: 

• Exercising regularly

• Eating a heart-healthy diet 

• Avoiding smoking

• Avoiding or limiting alcohol

• Getting enough sleep each night

6. Chest pain or shortness of breath

Although rare, chest pain and shortness of breath are serious side effects of Armour Thyroid. These side effects can result from elevated thyroid hormone levels putting stress on your heart.

In some cases, chest pain and shortness of breath could indicate a serious problem such as a heart attack. Your risk of a serious heart-related issue may be higher if you:

• Are taking too much Armour Thryoid

• Have a preexisting heart condition

• Are taking other medications that raise your risk of heart problems

If you experience chest pain or shortness of breath, call 911 or go to the nearest ER right away. Tell your healthcare team if you have any new or unusual heart symptoms while taking Armour Thyroid. They may need to check your thyroid levels and/or adjust your dose.

7. Bone density loss

Taking a thyroid hormone medication like Armour Thyroid can affect your bones — especially if your dose is too high. Over time, excess thyroid hormones can lead to weaker bones and a higher risk of bone fractures and osteoporosis.

You may be more likely to experience bone-related side effects if you:

• Are taking an Armour Thyroid dose that’s too high

• Already have low bone density

• Have been through menopause

• Have other osteoporosis risk factors, such as being older in age, having a family history, or taking certain medications

Talk to your healthcare team about your individual risk for bone loss, especially if you’ve been taking a thyroid hormone medication long term. They may recommend bone density testing or adjustments to your treatment. They can also give you tips to help keep your bones strong, such as:

• Getting enough calcium and vitamin D in your diet

• Incorporating weight-bearing exercises and strength training into your routine

• Avoiding smoking and heavy alcohol use

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Written by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

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