10 Things Patients Should Know About Armour Thyroid (Before using it!)

I'm a big fan of Armour thyroid (and other formulations of NDT) and have used it on many, many patients. 

But, like any prescription medication, Armour thyroid has some important aspects that you should be aware of as a patient. 

If you are someone who is considering using Armour thyroid, if you are someone who is already taking Armour thyroid, or if you just want to be an informed thyroid patient, then this is the article for you. 

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10 Important Facts About Armour All Thyroid Patients Should be Aware of

Armour thyroid is one of many available thyroid medications which your doctor can prescribe. 

Among thyroid medications, Armour is unique because of the hormones that it contains, how it is sourced, and how it impacts your body. 

structural formula of armour thyroid

As a thyroid patient, you should be aware of all of the potential side effects (and benefits) that come from ANY therapy that you are taking. 

In my opinion, the benefits of Armour far outweigh the potential downsides (for most patients). 

Let's dive into some important facts you should be aware of...

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#1. It's not the only NDT formulation. 

Armour thyroid is one of the oldest drugs available to treat hypothyroidism. 

It has fallen out of favor but because it's so old many physicians (both old and new) are aware that it exists. 

And, believe it or not, this plays a big role in why so many people are taking it. 

Many physicians are simply not aware of the newer medications (some of which have come out in the last year or two) such as Tirosint and Tirosint-Sol (these are T4 only medications but I'm using them to point out that most physicians are not educated when it comes to thyroid management). 

It's very possible, and perhaps probable, that your doctor is really only aware of a handful of thyroid medications. 

These may include medications such as Synthroid, levothyroxine, and perhaps Armour thyroid. 

If Armour thyroid is the only formulation of NDT that your doctor is aware of then it's probably the first thing that he/she will put you on if you don't do well on Synthroid/levothyroxine. 

This may be fine for some of you, but I want you to at least be aware of the other formulations as well. 

Why?

Because these formulations can be used in instances where you may not respond to Armour thyroid. 

Due to reasons such as inactive binders/fillers, you may not respond to Armour thyroid and it may actually make your symptoms worse. 

But, even if this does happen it doesn't mean that you need to avoid all formulations of NDT!

In fact, simply switching to another formulation of NDT may be enough to resolve your symptoms. 

Before you jump off the NDT bandwagon be sure to at least check out these other formulations. 

I've written in detail about these thyroid medications (and others) and their pros and cons on other articles which you can look to for more information. 

Other formulations of NDT include:

#2. Armour thyroid may be better for weight loss compared to other thyroid medications. 

I go over this topic a little more in detail on #7 when I discuss that many people actually prefer NDT formulations over T4 only formulations. 

You can skip there to see the studies which cite that Armour thyroid helps promote weight loss more than T4 only medications. 

Here, I just want to introduce you to that fact and explain it in a little more detail. 

Are some thyroid medications better at helping with weight loss?

The answer to this question is quite complex but I can say the answer is a definitive yes. 

I'm not going to go into all of the details why this is the case but I do want to point out one major reason. 

And that reason has to do with T3 thyroid hormone. 

T3 thyroid hormone is the most active thyroid hormone and Armour thyroid contains this medication. 

This is unique because most patients are taking Synthroid which does NOT contain T3. 

T3, because it is the most potent thyroid hormone, has been shown to directly stimulate your metabolism (2). 

By revving up your metabolism it will help increase your basal body temperature, normalize your heart rate, and improve the amount of energy that you burn. 

weight loss when using armour thyroid

All of these things contribute to the thermogenic effect (3) seen when using T3. 

So, T3 absolutely can help with weight loss but it shouldn't be used as a weight-loss therapy. 

What do I mean?

I mean that T3 thyroid hormone should only be used if you are deficient in this hormone. 

If you abuse it (meaning if you take it while still having normal thyroid function), you open the door to potentially causing harm to your body. 

The good news is that most people with thyroid-related issues ALSO have low T3 levels

This means that using T3, in this setting, is perfectly safe and healthy. 

In fact, it's probably just bringing your metabolism up to what it should be assuming you had a normal and healthy functioning thyroid. 

The fact that many people with thyroid disease are overweight probably suggests that many of these people have a sluggish metabolism due to their thyroid

#3. It's the most expensive formulation of NDT. 

Believe it or not, Armour thyroid is the most expensive formulation of NDT!

This information is according to the cash price (also confirmed by calling local pharmacies) on goodrx.com

This website shows the cash price of a 30 day supply of 60mg of Armour thyroid: 

cash price of armour thyroid

It will run you around $30.00 per month if you don't have insurance (sometimes it will be that price even if you do have insurance). 

You can compare this to other NDT formulations, such as Nature-throid, which is around $8.00 per month for 30 tablets of 60mg:

cash price of np thyroid

So, that's potentially a savings of around $20 per month (assuming cash price) if you use one formulation over the other. 

While price is certainly not the only thing you should consider, or even the most important thing you should consider, when looking at your thyroid medication, it can still be an important factor for many people. 

If you find that you've already tried Nature-throid or NP thyroid and they don't work for you then paying more for Armour thyroid may make sense. 

But if you are paying just because your doctor put you on it without trying other formulations then you may want to at least consider them. 

You can switch to a different formulation of NDT such as NP thyroid or Nature-throid on a grain for grain basis. 

So, let's say you are currently taking 1.5 grains (90 mg) of Armour thyroid. 

If you wanted to switch to Nature-Throid you would switch over to 1.5 grains (which happens to be 97.5mg). 

This would get you the same equivalent doses of T4 and T3 even though the mg dosage is slightly different (this doesn't affect the amount of T3 and T4 that you are consuming). 

#4. Armour thyroid contains animal products. 

Hopefully, this doesn't come as a surprise to you but Armour thyroid contains animal products. 

In fact, it is sourced from the thyroid glands of pigs (porcine-derived). 

Armour thyroid is created by taking the thyroid glands, mashing them, drying them out, and then ensuring that each 'grain' of medication contains a specific amount of T4 and T3 thyroid hormones. 

The fact that Armour comes from pigs is not necessarily a big deal by itself, but it certainly should be something that you are aware of. 

Why?

For a couple of reasons:

The first is that it contains animal proteins in addition to the thyroid hormones that your body needs. 

These animal proteins are important because they are not HUMAN proteins. 

It is possible (though it does not happen often) for your immune system to react negatively to these proteins and to trigger an immune response. 

This immune response may lead to the triggering of autoimmune thyroid symptoms from thyroid antibodies or other low-grade symptoms such as headache, fatigue, etc. 

This problem remains mostly a theoretical problem in that it's something that can potentially happen but doesn't occur in most people. 

For most people, your intestinal tract and stomach acid are sufficient to completely (or at least sufficiently) break down these animal proteins so that they don't enter into your bloodstream. 

As long as your body is producing sufficient stomach acid then this is probably not an issue you need to worry about. 

Also, by the way, there may also be some additional benefits to consuming animal glands beyond the benefits that thyroid hormone provides directly. 

Many supplements, including my thyroid/adrenal supplement, contain what are known as animal glandulars. 

These are desiccated and concentrated components of the glands of animals which seem to provide a stimulatory response in the body. They probably also contain ingredients which can help stimulate our own target organs. 

You can read more about these glandulars and how they may positively impact health here

While it may seem weird to consume the gland of another animal it's not that weird when you consider humans have been eating the organs of animals (such as the liver) for many health benefits. 

Liver, for instance, is incredibly high in Vitamin A and iron (4) and, as an organ meat, is considered to be a healthy source of vitamins and nutrients. 

nutrients found in liver

These organs meats were considered to be the healthiest part of the animal in some modern hunter/gatherer tribes. 

So try to forget about how weird it is and keep your eye on the benefits. 

#5. Armour Thyroid contains both T4 and T3. 

This one probably isn't a surprise for many of you but it's still worth pointing out. 

Armour thyroid falls into the class of Natural Desiccated Thyroid medications. 

These medications are notoriously beneficial because they contain more than just the standard T4 thyroid hormone (known as Thyroxine) in medications such as levothyroxine and Synthroid. 

Armour thyroid contains BOTH T4 and T3. 

Each grain of Armour thyroid contains 38mcg of T4 and 9 mcg of T3. 

This ratio is roughly about 77:23 which is somewhat close to the 80:20 ratio of T4:T3 that your thyroid gland produces naturally. 

Some doctors will suggest that Armour thyroid (and other NDT formulations) should not be used because they contain too much T3 compared to what the body produces naturally. 

But more recent studies (5) show that healthy thyroid glands produce around 80% T4 and around 20% T3. 

Some doctors try to suggest that the thyroid gland produces 95% T4 and 5% T3 (or somewhere near that amount) but these values are not supported by more recent studies. 

Why should you care that it contains T3?

I think the most important reason is that T3 is by far the most biologically active thyroid hormone (6). 

It's roughly 300x more potent than T4 at stimulating the thyroid receptors on your cells. 

Pretty much everything you want thyroid hormone to do stems from the direct actions of T3 thyroid hormone. 

Why isn't it used more frequently?

Most doctors are simply not comfortable using it or feel that it is too powerful or too difficult to dose. 

They can't, nor should they try, to downplay the effectiveness of T3 in stimulating thyroid receptors. 

This is probably one of the main reasons that many people do better on Armour thyroid compared to thyroid medications which contain just T4. 

#6. Armour thyroid contains other ingredients beyond just thyroid hormones. 

I mentioned this previously in another section when I discussed that Armour thyroid contains both T4 and T3. 

Because Armour is sourced from animal thyroid glands, it also contains additional ingredients which are also found inside of thyroid glands. 

This includes hormones, proteins, additional thyroid hormones, and probably other pre-cursors that we aren't aware of. 

Most important to this conversation is the fact that Armour contains the thyroid hormone T2 and Calcitonin. 

T2 is a biologically active thyroid hormone which is found in humans and seems to play an important role in regulating fat burn and metabolism (7). 

As long as you have a functioning thyroid gland your body will produce T2 in addition to T3 and T4. 

But, if you have had your thyroid gland removed by surgery or destroyed by RAI then your body isn't producing it anymore. 

For this reason, it has been suggested that Armour thyroid (and other brands of NDT) may be preferable to this patient population over T4 only formulations such as Synthroid. 

Why?

Because it can be argued that Armour provides a more complete array of thyroid hormones and other hormones which the body needs. 

It's of course still possible to not have a thyroid and do somewhat well on T4 only medications, but the chances are high that you will feel even better on a T4 + T3 combination, especially one that includes the other thyroid hormones such as T2. 

This concept has become more popular recently as studies have shown that people without a thyroid tend to have lower T3 levels than healthy people if they only take T4. 

I suspect that over the coming years (perhaps around 10 years or so) it will be much more common for people without a functioning thyroid to be placed on a combination of both T4 and T3. 

#7. It has a better track record compared to levothyroxine/Synthroid. 

Surprisingly, this is not only my own personal opinion but also the opinion of certain clinical studies. 

Researchers have already done some of the heavy lifting for us so let's evaluate one study to get a better idea of how people respond to medications such as Armour thyroid. 

In this study (8), researchers placed patients on either levothyroxine or thyroid extract (another name for NDT). 

They kept these patients on these medications for 16 weeks and then swapped them to another medication. 

So some patients were placed on levothyroxine first for 16 weeks and then transitioned to thyroid extract for another 16 weeks. 

The other group of patients were on thyroid extract first for 16 weeks and then transitioned to levothyroxine for another 16 weeks. 

At the end of this 32 week period they then simply asked patients how they felt on the different medications. 

What did they find?

They found that those people who were on thyroid extract (abbreviated DTE which stands for desiccated thyroid extract) experienced more weight loss compared to the people who were only levothyroxine alone. 

comparison of weight loss on armour thyroid vs levothyroxine

The study also concluded that about half of the people or around 48.6 percent of people had a preference for DTE over levothyroxine. 

They also showed that patients lost around 4 pounds simply switching thyroid medication and had a subjective improvement in their symptoms (meaning they felt less fatigue, less hair loss, fewer aches/pains, better concentration, better sleep, improved memory, etc.). 

One important factor that this study revealed was that people who are overweight and those with a higher reverse T3 level tend to prefer NDT over T4. 

So if you are someone who has some extra weight to lose your body may do better on Armour. 

If, on the other hand, your weight is relatively normal (or just slightly higher than you'd like), T4 only medication may be preferable. 

This isn't an exact science but something to consider. 

Lastly, another important point worth mentioning is that people in this study did NOT experience any negative side effects on either therapy which suggest that Armour (if dosed correctly) is quite safe. 

#8. It is not the name brand of NP thyroid. 

This is important to understand because your pharmacy likely considers Armour thyroid to be the name brand for NP thyroid

Both medications are formulations of Natural Desiccated Thyroid but they are certainly not the same. 

Both medications have the same amounts of T4 and T3 in them grain for grain but they do differ in their inactive ingredients. 

Armour thyroid contains the following ingredients (9):

  • Triiodothyronine (active ingredient)
  • Thyroxine (active ingredient)
  • Calcium stearate
  • Dextrose
  • Microcrystalline cellulose
  • Sodium starch glycolate
  • Opadry white
  • Minor amounts of calcitonin, T1, T2, and proteins
inactive and active ingredients found in armour thyroid

NP thyroid contains the following ingredients:

  • Triiodothyronine (active ingredient)
  • Thyroxine (active ingredient)
  • Calcium stearate
  • Dextrose monohydrate
  • Maltodextrin
  • Mineral oil
  • Minor amounts of calcitonin, T1, T2, and proteins
active and inactive ingredients found in NP thyroid

Why does this matter?

Because the inactive ingredients found in these medications may have an impact on how well you tolerate it! 

Switching from Armour to NP thyroid or from NP thyroid to Armour may actually be enough to trigger the onset of hypothyroid symptoms. 

You should be aware of the difference between these medications so that you know if your pharmacy tries to swap the medications on you without you knowing it. 

And yes, pharmacists can do this because these medications are considered "bioequivalent" (10) from the insurance perspective. 

So if your insurance wants the cheaper formulation (which is NP Thyroid), your pharmacist can make the switch. 

If you want to ensure that you get Armour thyroid filled you may need to have your doctor write "dispense as written" on your prescription. 

In addition, you can make a special request for Armour thyroid when you go to pick up your medication and just pay the cash price. 

Don't be afraid to do this, especially if you feel worse on NP thyroid, because the cash price is typically around $20-30 per month. 

It may be worth the extra expense if it dramatically improves your quality of life. 

#9. Transferring from levothyroxine to Armour requires dose adjustments. 

If you are switching from levothyroxine or Synthroid over to Armour thyroid then you must consider how to adjust your dose during the transition. 

Unfortunately, it's not as easy as just saying "well, I'm taking 100mcg of levothyroxine so I will need 100mg of Armour thyroid". 

Why is the transition so difficult?

The main reason has to do with the fact that Armour thyroid contains T3 in addition to T4. 

And, because T3 is so much more powerful when compared to T4 it's difficult to pinpoint what an equivalent dose would be. 

Most standard textbooks will give you a conversion chart which looks similar to this:

converting T4 to armour thyroid

The standard conversion states that 100mcg of Synthroid/levothyroxine is equal to 60mg of Armour thyroid. 

But there's one big issue with this conversion chart...

Most people who go by this conversion chart end up with a rising TSH and persistent symptoms of hypothyroidism when they transition. 

These symptoms seem to suggest that using this chart results in insufficient dosing. 

In fact, newer studies (11) suggest a conversion which is more similar to this:

updated armour thyroid to levothyroxine conversion chart

This chart suggests that 100mcg of T4 is equivalent to 68mg of Armour thyroid (which is more than the "standard" conversion listed above). 

My own personal experience suggests that 1 grain of Armour thyroid is probably closer to 75mcg of T4. 

Because there's quite a bit of debate about how to transition appropriately, just be sure that you give your body enough time to acclimate to the changes and be sure to monitor your thyroid lab tests

Also, don't be alarmed if you suddenly increase some worsening symptoms upon transitioning. 

This will most likely be temporary and is probably related to your dose, especially if it is insufficient. 

#10. Armour may impact your thyroid lab tests differently than other thyroid medications. 

Lastly, you should be aware that Armour thyroid causes some changes to your thyroid lab tests which are not necessarily the same as levothyroxine. 

Because Armour contains T3 it tends to cause a more pronounced and powerful drop in your TSH. 

It has been estimated that T3 is roughly 3-4x more potent (12) than T4 at reducing the TSH. 

This may cause more of a drop in your TSH than you are used to with other T4 only medications. 

In addition, because it contains T3, Armour will cause a more pronounced increase in your free T3 levels. 

It may also cause a drop in your free T4 levels as well. 

This pattern may be confusing to newer patients (and plenty of physicians) so it is something you should be aware of. 

The pattern itself is not necessarily an issue but it may make interpreting your lab tests slightly more difficult. 

To recap, you may find the following changes to your thyroid lab tests when transitioning to Armour thyroid:

*Note: These are only rough guidelines and may not apply to all patients. 

Conclusion

Armour thyroid is a great thyroid medication but it's certainly not the only game in town. 

I find that Armour thyroid is a great option, especially for patients who do not have a thyroid or in whom their thyroid has been destroyed. 

This is probably because it contains special ingredients and thyroid hormones not found in other formulations. 

But, that doesn't mean it won't or can't work for other patient populations as well. 

I find that Armour (or other formulations of NDT) represent a GREAT starting point for many thyroid patients. 

Now I want to hear from you:

Are you someone who is currently using Armour thyroid?

Are you someone considering using Armour thyroid?

If you are taking it, how are you responding?

Do you feel your dose is adequate?

If you are considering it, what things are preventing you from using it?

Leave your questions or comments below! 

References (Click to Expand)

This post was most recently updated on August 6th, 2019

Dr. Westin Childs

Dr. Westin Childs is a Doctor of Osteopathic Medicine. He provides well-researched actionable information about hormone-related disorders and formulates supplements to treat these disorders.He is trained in Internal Medicine, Functional Medicine, and Integrative Medicine. His focus is on managing thyroid disorders, weight loss resistance, and other sex hormone imbalances.You can read more about his own personal journey here.

6 thoughts on “10 Things Patients Should Know About Armour Thyroid (Before using it!)”

  1. Started Armour a month ago. T3 was below range, Reverse T3 was above the range. I feel worse on it. Dr is switching me to T3 only to see how I do which he is only doing because I suggested after binging on all your great info. Appreciate all the info you put out. I get more clear info from you over all the Drs I have seen year to year. Now to just get whatever undiagnosed autoimmune disease under control. I look much younger than I am and although T3 is low I am very lean and in good shape. So every Dr assumes I am healthy. Sick of hearing why are you here your young and in great shape. And then they have no answer and just refer me to the next Dr.

  2. My endocrinologist says it would be too difficult to regulate Armour. I am currently on a Levothyroxine dose of .075, 6 days a week. She has steadily decreased my Levothyroxine over the past 9 months. I feel worse now then I did last October—anxious, unexplained sweating, hair loss, achy joints, heart palpitations. I’ve about had it. Would Armour be an easy switch?

    • Hi Barbara,

      Most endocrinologists believe that NDT is somehow more difficult to regulate compared to T4 but this just isn’t the case. I think it’s used as an excuse so they don’t have to try.

      But, to answer your question, the switch isn’t always an easy one. Sometimes it is and sometimes it isn’t and there just isn’t a great way to tell if it will be before hand.

  3. Dr Childs,

    You mentioned a potential increase (or decrease) in Reverse T3 after switching to Armour. What do you think the causes are of an increase and any way to combat it other than switching medication?

    Many thanks!

  4. In 1997 I had to take radioactive iodine for Graves disease. I have been on all different thyroid medication and doses trying to feel as good as I did before thyroid disease and get my levels corrected. I was prescribed 180 mgs of Armour Thyroid by a holistic doctor recently and I was starting to feel halfway decent. This doctor has since moved and so I went to an endocrinologist. He feels that dose is too high and it is not good for my heart because my TSH was out of range. My Free T3 & Free T4 was in range, but very low. He now has me on 135 mg of Armour and I feel terrible (I slowly weaned off the higher dose). I see him again on the 27th of this month. Is it true the higher dose will affect my heart even though I had no hyper symptoms? I thought if your T3& T4 is in range then you are not taking too much thyroid medication. Your thoughts?

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