Armour Thyroid and Other Desiccated Thyroid Extract (DTE) Drugs

Other brands include Nature-Throid, NP Thyroid, and WP Thyroid

Desiccated thyroid extract (DTE), also known as natural desiccated thyroid (NDT) and porcine thyroid, is a prescription medication made from the desiccated (dried) thyroid glands of animals. DTE drugs, which include the brand names Armour Thyroid, Nature-Throid, NP Thyroid, and WP Thyroid, have been around for decades and remain popular with holistic, alternative, and integrative physicians as a thyroid hormone replacement treatment for underactive thyroid (hypothyroidism).

History

First used in the early 1890s, natural thyroid preparations, mostly DTE, were the standard treatment for hypothyroidism until the mid-1970s.

The earliest forms of natural thyroid came from the thyroid glands of cows, but early in the 1900s, the Armour meat company got into the thyroid medication arena, marketing its own natural desiccated thyroid from pigs, known as Armour Thyroid. All commercial DTE now comes from pig thyroids.

DTE contains both thyroxine (T4) and triiodothyronine (T3), as well as a hormone called calcitonin and other compounds. A normal human thyroid gland produces T4, T3, and calcitonin as well.

When synthetic T4 (levothyroxine) was first available in the 1950s, doctors were reluctant to prescribe it because they were afraid that since it didn't have T3 as DTE does, it might cause people to end up with T3 deficiencies. It was also considerably more expensive than DTE.

Around the same time, there were starting to be serious concerns about the potency of DTE. With a limited shelf life and major variability in the amount of active hormones found in the medication (it could contain anywhere from twice the amount needed to none at all), DTE began to get a bad reputation from which it hasn't totally recovered, despite the fact that in 1985, revised U.S. Pharmacopeia content standards made the potency stable.

In 1970, scientists discovered that T4 converts to T3, alleviating the previous worry that levothyroxine as a standalone treatment could lead to T3 deficiency. In addition, the specific lab test to check thyroid stimulating hormone (TSH) levels was developed in 1971, giving doctors a way to better monitor the effects of hormone replacement medication.

New awareness of T4's conversion to T3 and the advent of the TSH test sparked the trend toward increasing numbers of physicians prescribing levothyroxine as the sole treatment for hypothyroidism. By 1974, the treatment recommendations proclaimed levothyroxine "the agent of choice."

Despite the preference toward levothyroxine, DTE started to make a resurgence in the 1990s as interest in natural medicine increased. At that time, patients who weren't feeling well on levothyroxine were also becoming more empowered and aware of treatment options—like Armour Thyroid, Nature-Throid, and other desiccated thyroid drugs—thanks in part to the internet.

Who It's For

While most people do well on the standard treatment of levothyroxine, some people still have hypothyroid symptoms and/or low T3 levels while taking it, even though their TSH levels are within normal limits. Scientists don't understand exactly why this is, but it could be due to problems with the way the pituitary gland, thyroid, and hypothalamus—all of which work together to stimulate thyroid hormone production—communicate with each other.

If you're currently taking levothyroxine (brand names include Synthroid, Levoxyl, Unithroid, and Tirosint) and you're still not feeling well, you may benefit from adding liothyronine (synthetic T3) or switching to DTE.

Benefits

There are several potential benefits of taking DTE.

Many Patients Prefer It

A 2018 online survey of 12,146 patients being treated for hypothyroidism with levothyroxine, levothyroxine with liothyronine (T3), or DTE, found that the people taking DTE were happier with their treatment and their doctors than people on the other two types of therapy. The DTE group also reported fewer problems with memory, weight, fatigue, and energy than the other two groups.

You May Be More Likely to Lose Weight

A 2013 study compared DTE to levothyroxine, evaluating 70 patients ages 18 to 65 who had primary hypothyroidism. The patients were randomly assigned to either natural desiccated thyroid or levothyroxine for 16 weeks, and then switched to the opposite for 16 weeks. Neither the researchers nor the patients knew who was taking what.

At the end of the study, there were no remarkable differences between DTE and levothyroxine in terms of heart rate, blood pressure, or thyroid hormone levels, but HDL cholesterol ("good" cholesterol) was reduced.

In this study, patients on DTE lost an average of 3 pounds during their DTE treatment.

When asked whether they preferred the first or the second regimen, nearly 49 percent of the participants preferred DTE, almost 19 percent preferred levothyroxine, and about 33 percent had no preference.

Some Report an Improvement in Symptoms

In the 2013 study, some of the patients who preferred DTE said their mood and mental symptoms, such as happiness, memory, concentration, sleep, and energy level, were greatly improved while taking DTE. However, overall the study measured no significant differences in general health, or in neuropsychological testing, during treatment with DTE vs. T4.

Furthermore, a meta-analysis of 11 randomized trials with a total of 1216 patients, in which treatment with T4 was compared to combination treatment with T4 and T3 found no improvement in body pain, depression, anxiety, quality of life, or body weight with combination treatment.

The bottom line is that, while some individuals may indeed feel better with combination treatment, treatment with T4 alone appears to be entirely sufficient for the great majority of people with hypothyroidism.

Cost Is Similar

Armour Thyroid is the most expensive brand of desiccated thyroid extract, but other DTE brands like Nature-Throid, NP Thyroid, and WP Thyroid are comparable or cost less than brand names of levothyroxine.

Drawbacks

There are some possible drawbacks to choosing DTE as your treatment too.

Potential Shortages

Sometimes there are shortages of DTE, as there was in 2009 to 2010. When this happens, you may have to switch to another brand or order your DTE from Canada (brand name: ERFA Thyroid).

Market Fluctuations

DTE is vulnerable to the market conditions affecting pork. For instance, in 2013 to 2014, an epidemic of porcine epidemic diarrhea virus wiped out an estimated 8 million pigs in the United States. The virus killed as many as 10 percent of the country's pig population, driving up prices for pork products, including DTE.

Hormonal Concerns

There are slightly varying amounts of T4 and T3 in DTE, making them a less precise treatment option and potentially creating more difficulty in finding the correct dosage. As an example, Armour Thyroid states that the active ingredients in their medication are "similar" from tablet to tablet.

Animals have different balances of hormones than humans. DTE contains a 4:1 ratio of T4 to T3; humans have a ratio of 14:1. This can translate into high T3 levels in people taking DTE.

Because T3 is about four times stronger than T4, there's concern that taking DTE or a synthetic combination of T4/T3 (levothyroxine and liothyronine) can temporarily result in thyrotoxicosis two to four hours after taking it.

Thyrotoxicosis is a condition that occurs when you have too much thyroid hormone in your body. In order to combat this, if you're taking DTE or synthetic T4/T3 therapy, your free T4 and free T3 levels should be tested right away in the morning to make sure that even when they're at their peak, they're still within normal ranges.

Pregnancy

The fetus through the first 18 weeks of gestation depends on T4 for normal neurological development, and higher-than-normal levels of T3 have been associated with impaired neurological development. Because the ratio of T4:T3 are much lower with desiccated thyroid (4:1 in pigs vs 14:1 in humans), desiccated thyroid generally should not be used in women of childbearing age.

Risks and Considerations

As with any medication, there are some potential risks when you take DTE.

Improper Use

Whether synthetic or natural, thyroid hormones shouldn't be used to treat obesity or to help with weight loss. Taking a thyroid hormone supplement may help you lose weight initially, but research has shown that most people gain it all back once they stop taking or reduce the amount of hormone. Another concern is that taking too much thyroid hormone or using it along with other weight loss drugs can result in serious and potentially life-threatening complications.

Contraindications

You shouldn't use DTE if you're allergic to any of the ingredients it contains, such as pork, or if you have an overactive thyroid or untreated adrenal issues. You also should not take DTE if you are a woman of childbearing age.

Other Serious Health Conditions

If you have other medical conditions like diabetes, heart disease, adrenal problems, or issues with your pituitary gland, your medications for these may need to be adjusted when you're taking DTE.

Medication Interactions

Be sure to tell your doctor about all prescription or over-the-counter medications, vitamins, supplements, and herbal products you're taking, as DTE can have interactions with many of these.

Pregnancy

If you're pregnant, nursing, or plan to become pregnant, talk to your doctor about taking DTE. Let your doctor know if you become pregnant while you're taking DTE as well.

Supplements and Out-of-Country Purchases

Over-the-counter glandular thyroid support supplements are neither the same as prescription DTE, nor a substitute for prescription thyroid hormone replacement medication. It can also be dangerous to your health to buy DTE from another country without a prescription and without your doctor's approval and supervision.

The T4/T3 Thyroid Drug Controversy

As noted, the standard treatment for hypothyroidism is levothyroxine (T4) alone. The addition of T3 to the levothyroxine/T4-only treatment—or using DTE—is controversial and the topic of ongoing research and discussion.

Once experts realized that T4 naturally converts to T3, there was a great deal of excitement about how modern levothyroxine was compared to DTE, which was considered old-fashioned. At that time, many doctors switched patients over to the synthetic medication and never looked back.

Still, some of these patients complained after being switched to levothyroxine that their symptoms had worsened or couldn't be resolved. This led to a number of the doctors who had previously prescribed DTE for their patients putting some of them back on it.

DTE is prescribed far less often than levothyroxine. But frustrated patients who don't feel well who are doing their research and talking to other people. As a result, they're becoming increasingly aware that there are options beyond levothyroxine and that some people feel better on DTE.

FDA-Approved?

Because DTE was developed before the U.S. Food and Drug Administration (FDA) existed, its legality as a prescription medication was grandfathered in. While it's regulated by the FDA, it has never gone through the application process that was required of new drugs introduced to the market after the FDA was founded. This means that it's not FDA-approved.

How to Talk to Your Doctor About DTE

If you're being treated for hypothyroidism with levothyroxine alone and you still have symptoms of persistent hypothyroidism, talk to your doctor about the possibility of trying DTE. Though it has been in use for more than 100 years, DTE is still somewhat controversial and it can be a challenge to find doctors who will prescribe it. Most doctors today were taught in medical school that levothyroxine is the only acceptable option for treating hypothyroidism.

Along with that, many doctors aren't aware that DTE is still available or that it can be used safely to treat some hypothyroid patients. Some believe that prescribing DTE is difficult. These ideas are unfortunately reinforced by negative opinions from levothyroxine sales representatives, unfounded rumors that DTE is going off the market, and other anecdotal information.

Let your doctor know that you've done your homework on DTE and that recent studies have shown that it can be very beneficial for people who aren't doing well on levothyroxine. Though, in 2012, the American Thyroid Association said that DTE should not be used to treat hypothyroidism, it conceded in its 2014 recommendations that some people respond well to DTE or a combination of synthetic T4/T3 therapy.

A Word From Verywell

If your doctor absolutely refuses to entertain DTE as an option without offering you a very good reason that's specific to your individual health, it may serve your best interest to seek another opinion from a different practitioner, such as an integrative or holistic physician who's comfortable with the full range of thyroid medication options, instead of an endocrinologist. Choose a practitioner who's familiar with prescribing and monitoring patients on DTE.

Was this page helpful?
Article Sources