The Desiccated Thyroid Story

What desiccated thyroid is

T4 only, or T4 and T3? Synthetic or natural thyroid supplementation?

These questions come up repeatedly in discussions about medications for hypothyroidism. To read about the T4 and T3 thyroid hormones, see T3 Supplementation.

Desiccated (dried, sometimes misspelled as dessicated) thyroid is thyroid hormone derived from pigs' thyroids, usually in pill form. It contains both of the main thyroid hormones T4 and T3, and probably the lesser-known hormones T2 and T1. (T2 and T1 aren't measured in desiccated thyroid, but they were in the pigs' thyroids, and they aren't removed.) Its use began in the late 1800s and has continued to the present. (See Hypothyroidism Treatment History for details.)

Where desiccated thyroid is

The best-known brand name is Armour, which is sold in the US and imported in some other countries. In Canada, desiccated thyroid known simply as Thyroid is made by Erfa (formerly by Pfizer Canada, and before that, by Parke-Davis). Most pharmacies in both the US and Canada carry desiccated thyroid medication.

In the UK, only a few pharmacies carry Armour, but other desiccated thyroid products are more widely available. A thread with information about the availability of desiccated thyroid in the UK, the Netherlands, Belgium, Germany, Denmark, and Norway is online here.

See Country Specific for links to sites with more information relevant to specific countries.

The synthetic thyroid alternatives

In contrast to desiccated thyroid, most synthetic medications contain T4 only. Common brand names include Eltroxin, Levothroid, Levoxyl, Synthroid, and Unithroid. Thyrolar is a synthetic medication that contains T4 and T3.

Pharmaceutical company representatives typically say that synthetic medications for hypothyroidism are superior to desiccated thyroid. They may say that desiccated thyroid is unstable. Since these sales representatives are the primary source of information about drugs for most doctors, many doctors will say the same to their patients.

For many patients, synthetic medications are adequate and sometimes preferable, especially when T4 and T3 are taken together. For many other patients, however, synthetic medications didn't or don't relieve all their symptoms, while desiccated thyroid does. It's hypothesized that the thyroid hormones T2 and T1, and unidentified "piggy bits," play roles that are not yet understood.

Unlike desiccated thyroid, synthetic medications have often been recalled due to batch inconsistencies. Yet doctors are led to believe that desiccated thyroid is unstable. Forest Pharmaceuticals, the manufacturer of Armour, addressed the question of batch-to-batch stability at the Armour Thyroid site:

To ensure that Armour® Thyroid tablets are consistently potent from tablet to tablet and lot to lot, analytical tests are performed on the thyroid powder (raw material) and on the actual tablets (finished product) to measure actual T4 and T3 activity. Different lots of thyroid powder are mixed together and analyzed to achieve the desired ratio of T4 to T3 in each lot of tablets.

The Armour Thyroid site appears to no longer has the above information, but it was quoted from that site.

Numerous medical articles discuss the supposed superiority of synthetic T4 over T4/T3 combinations, whether synthetic or natural. These articles are generally based on theoretical views and lab results that look at only part of the picture and not at patient outcomes. Since teaching about the use of desiccated thyroid in medical schools stopped in about 1975, the onus is often on patients to provide physicians with information about this medication.

How to get desiccated thyroid

Desiccated thyroid is a prescription medication, so patients can choose to take it only if doctors are willing to prescribe it. We've put together some tips on finding a good thyroid doctor. To try to convince your current doctor to prescribe desiccated thyroid, you can bring medical references (see the column at the right) or send them to your doctor before your appointment and ask your doctor to prescribe at least a trial amount of desiccated thyroid.

Treatment with desiccated thyroid

According to the Armour Thyroid site, the ratio of T4 to T3 in Armour desiccated thyroid is 4.22 parts of T4 to one part of T3. This higher-than-human ratio of T3 to T4 means that T3 levels are typically higher than T4 levels in patients taking desiccated thyroid. Some patients take some synthetic T4 with desiccated thyroid to balance the ratio, while others do fine on desiccated thyroid only.

Because of the T4/T3 ratio in desiccated thyroid, it's especially advisable to monitor free T3 and free T4 levels in addition to or instead of TSH levels when taking desiccated thyroid. As always, symptoms — or lack of them — will help indicate whether the dose is suitable or not.

The results on desiccated thyroid

Some people feel the effects within minutes of taking desiccated thyroid. For others, the effects may take as long as six weeks to be felt. Regardless of how long it takes to notice the effects, it may still take months to feel normal again. (This is also true with synthetic medications.) The body needs time to heal from the results of insufficient thyroid hormone.

The desiccated thyroid references

See the links at the right on this and all the pages in the Desiccated Thyroid section of this site. The Desiccated Thyroid References page provides an overview of the references and why we need them. The compilations of references are divided into medical journal references and references from other sources, and each has a printer-friendly version so that you can take these references to your doctor if they're relevant to your situation.

On the "Patients' Experiences" pages, you can read how, for many hypothyroid patients, treatment with desiccated thyroid brought back their health.

More information about desiccated thyroid

TSH levels may be another piece of the puzzle to feeling well. See also our TSH Levels article and links.

More information about desiccated thyroid is on our Hypothyroidism Medication and Hypothyroidism Medication Comparison pages.

Lois Summers