Armour Thyroid vs. Levothyroxine for Hypothyroidism: 7 Differences You Should Know

If you have hypothyroidism (low thyroid hormone levels), your healthcare provider will typically recommend thyroid replacement therapy. For most people, levothyroxine (Synthroid, Levoxyl, Tirosint, Unithroid) is the first treatment that’s recommended. It’s a synthetic (man-made) version of T4 thyroid hormone.

While levothyroxine is the first-choice treatment for hypothyroidism, you may have heard that there are other options. Armour Thyroid (desiccated thyroid) is an older type of thyroid replacement that’s sometimes referred to as natural thyroid. This medication differs from levothyroxine in several key ways, which may determine whether or not it's right for you.

1. Armour Thyroid and levothyroxine are made differently

Synthetic thyroid medications made their debut in the late 1940s. Before that, desiccated thyroid extracts, like Armour Thyroid, were the most common form of treatment for hypothyroidism.

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Today, thyroid extracts are made from the dried and ground thyroid glands of pigs. So they’re often considered a more “natural” form of thyroid replacement. Along with Armour Thyroid, NP Thyroid is another natural thyroid option available on the market.

In contrast, levothyroxine is a synthetic thyroid hormone that’s made in a laboratory. It’s available as generic levothyroxine and as brand-name Synthroid, Levoxyl, and Tirosint.

2. Each product contains different thyroid hormones

The two main hormones made by your thyroid gland are T4 (thyroxine) and T3 (triiodothyronine). T4 is an inactive form of thyroid hormone. Your body converts a portion of T4 into T3, the active form.

Armour Thyroid and levothyroxine contain or mimic different thyroid hormones. Armour Thyroid contains both T4 and T3 thyroid hormones, in addition to fillers and binders to hold everything together.

Levothyroxine contains a synthetic version of T4 thyroid hormone. So your body will need to convert the T4 to T3 to have an effect. The medication also contains fillers and binders, and most tablets (but not the capsules) have artificial colors added.

For many people, supplementing T4 alone with levothyroxine is enough to raise low thyroid hormone levels. But your healthcare provider may recommend adding synthetic T3 (liothyronine), which you would need to take separately.

3. The dosages for Armour thyroid and levothyroxine are different

When you first start thyroid replacement therapy, you’ll typically begin with a lower dose. If needed, your healthcare provider will gradually increase it over time. Adjustments may be made based on your lab results, any medical conditions you have, and what medication you’re taking. Your age and weight can also determine your dose.

The dosages for Armour Thyroid and levothyroxine are different  For starters, Armour Thyroid is available in “grains.” One grain (or about 60 mg) contains 38 mcg of T4 and 9 mcg of T3. The tablets are available in a range of doses from 15 mg (¼ grain) to 300 mg (5 grain).

Levothyroxine is available in micrograms. The tablets come in doses ranging from 25 mcg to 300 mcg of T4. It’s estimated that 1 grain of Armour Thyroid is about the same as 88 mcg of levothyroxine.

For children, body weight determines the doses for both medications. For adults, the dose is calculated based on body weight only in the case of levothyroxine.

For both medications, it’s best to take doses in the morning and on an empty stomach. This helps your body absorb more of the medication, making it more effective.

4. Levothyroxine products may have less variability

Thyroid replacement medications have a narrow therapeutic index. This means that small changes in your dose can significantly affect how well the medication works. So it’s important that you receive the correct amount of thyroid hormones in each dose.

Levothyroxine products are made to consistently contain the correct amount of T4 in each dose. Brand-name and generic levothyroxine products have been shown to work just as well. And switching between generic products doesn’t appear to be an issue.

Desiccated thyroid extracts like Armour Thyroid are more complicated. In some cases, these products may not be as consistent between batches. In other words, you could receive too little (or too much) T4 and T3 depending on the pill. In fact, recalls of these products regularly happen for this reason.

5. Armour Thyroid has unique risks to consider

Because of how it’s made, Armour Thyroid has a few unique risks compared to levothyroxine.

It’s not FDA approved 

Unlike levothyroxine, desiccated thyroid medications, like Armour Thyroid, aren’t FDA approved. These products were on the market before FDA regulations around new medications were in place. So the FDA hasn’t reviewed their safety and effectiveness.

It contains a different ratio of thyroid hormones 

There’s a risk of getting too much T3 from medications like Armour Thyroid. The ratio of T4 to T3 is different from what’s normally produced in humans.

There can be potential contamination risks

Armour Thyroid is made at a facility that also handles cow tissues. So there’s a potential risk of contamination with viruses, bacteria, or other germs. However, the manufacturer has stated there haven’t been any cases of disease transmission with Armour Thyroid.

6. Levothyroxine is considered the gold standard for hypothyroidism treatment

Experts consider levothyroxine to be the first-choice medication for treating hypothyroidism. This is because it works well and doesn’t have too many side effects. 

Levothyroxine is generally preferred over medications like Armour Thyroid. In addition to the risks discussed above, there isn’t a lot of long-term safety data on thyroid extracts.

What’s more, levothyroxine is specifically preferred as a treatment for pregnant women. That’s because the T3 in thyroid extracts can’t reach a developing baby’s brain. Because of this, Armour Thyroid shouldn’t be used to treat hypothyroidism during pregnancy.

7. Some people report feeling better with Armour Thyroid compared to levothyroxine

There aren’t many studies comparing Armour Thyroid and levothyroxine. But current data suggests that the T3 in Armour Thyroid doesn’t have additional benefits over taking T4 alone. However, some people report feeling better when they take Armour Thyroid than when they take levothyroxine.

A recent study of 250 people found that those who switched from levothyroxine to Armour Thyroid felt better overall. But, compared to levothyroxine, more people stopped taking Armour Thyroid before 6 months of treatment. This was due to things like side effects and lack of symptom improvement.

Another, smaller study that included 70 people also showed a preference for desiccated thyroid over levothyroxine. In this case, the people who preferred desiccated thyroid lost weight and reported significant improvement in symptoms related to memory, concentration, and sleep. Even so, more research is needed to confirm any differences in effectiveness and side effects. 

Can you switch from Armour Thyroid to levothyroxine?

Armour Thyroid and levothyroxine aren’t interchangeable. But it’s possible to switch from one medication to the other. This should be done under the supervision of a healthcare provider and will require a new prescription.

Your dose will change if you switch medications. But your healthcare provider can help you find the closest match. They’ll also monitor your labs to make sure the new medication is working well for you.

How to save on prescription thyroid medications

There are many ways to save on your prescription thyroid medication. Consider taking advantage of GoodRx coupons, manufacturer savings cards, and more.

Save on Armour Thyroid

There are ways to save on Armour Thyroid, which is available as a brand-name medication. GoodRx can help you navigate between GoodRx coupons, copay savings cards, and patient assistance programs to save money on your prescription.

• Save with GoodRx: Anyone with a valid prescription, regardless of insurance status, can use GoodRx to purchase a 30-day supply of Armour Thyroid at an exclusive cash price of $34.50.

• Save with a copay savings card: If you have commercial insurance, you may be eligible to pay as little as $35 for a 30- or 90-day prescription of Armour Thyroid using a savings card from the manufacturer.

• Save with patient assistance programs: If you’re uninsured or underinsured, you may be eligible for Armour Thyroid’s patient assistance program, which offers the medication free of charge.

Save on levothyroxine

Levothyroxine is available as a generic tablet and capsule. At certain pharmacies, generic levothyroxine’s price may be as low as $4.00 with a GoodRx coupon.

Levothyroxine tablets are also available as a number of brand-name products, including Synthroid, Levoxyl, and Unithroid. If you’re eligible, you could pay as little as $25 a month for Synthroid with a manufacturer savings card. And you may be able to pay as little as $4.00 for Levoxyl with a GoodRx coupon. Unithroid may cost as little as $3 a month with a manufacturer savings card.

Tirosint and Ermeza are examples of brand-name levothyroxine oral solutions. If you have commercial insurance, you could pay as little as $25 a month for Tirosint with a manufacturer savings card. The price for Ermeza may be as low as $276.53 at certain pharmacies with a GoodRx coupon.

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Written by:

Kristianne Hannemann, PharmD

Kristianne Hannemann, PharmD, is a licensed pharmacist in California. She has been a retail pharmacy manager and staff pharmacist for over 7 years and has contributed drug information content to different health companies.

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:

Sanjai Sinha, MD

Sanjai Sinha, MD, is a board-certified physician with over 20 years of experience. He specializes in internal medicine.

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