Thyroid Drugs: Synthetic vs. Natural?

By: | Comments: 0 | August 3rd, 2011

If you have an underactive thyroid – hypothyroidism – there is an important controversy regarding your medication that you’ll want to be aware of – particularly if you don’t feel well after treatment.   The controversy centers on the drug most often prescribed for hypothyroidism, versus other drugs.
The majority of endocrinologists and mainstream physicians favor only one hypothyroidism treatment: the drug levothyroxine, a synthetic form of the thyroid hormone thyroxine. Levothyroxine is also known as l-thyroxine, and is sometimes abbreviated as T4, to refer to the fact that thyroxine has 4 iodine atoms. The most popular brand name of levothyroxine is Synthroid, but other brands you might hear about include Levoxyl, Levothroid, and Unithroid. Generic levothyroxine drugs are also made by several manufacturers.
Before levothyroxine was introduced, the thyroid hormone replacement drug of choice was natural desiccated thyroid. Natural desiccated thyroid is known primarily by its brand names of Armour Thyroid and Naturethroid. Natural desiccated thyroid is “porcine thyroid” – meaning that it’s derived from the thyroid gland of pigs. Desiccated thyroid includes thyroxine, as well as triiodothyronine, the active thyroid hormone that is also referred to as T3. It also includes other thyroid hormones found in an actual gland, including T1 and T2.
When levothyroxine was introduced decades ago, it was launched with great fanfare and marketing, and a price much higher than its competition. Levothyroxine was touted as more “modern” and “reliable” than the “old-fashioned” and “out of date” natural thyroid drugs. The medical establishment’s tendency to favor whatever is newest and most expensive on the market, coupled by intensive promotion by the drug’s manufacturer, meant that levothyroxine soon dominated the market for thyroid hormone replacement drugs, and became quite profitable for its manufacturers.
Today’s generation of doctors are, in fact, trained in medical school that the only treatment for hypothyroidism is levothyroxine. Many of them even believe — despite the fact that there is absolutely no research to support it — that today’s natural desiccated thyroid drugs are unreliable, unstable, ineffective, or even dangerous. It’s common to hear doctors erroneously describe desiccated thyroid drugs as “being from cows” (it’s porcine, as mentioned), or “available over-the-counter” (it’s not, it requires a prescription). Some doctors don’t even believe or know that natural desiccated thyroid is still a legal, FDA-regulated, prescription-only drug.
The truth is that natural desiccated thyroid drugs are regulated by the FDA, and must meet stringent quality control, stability and potency standards like any other prescription medication.
Despite the predominance of levothyroxine treatment, there has been a growing shift to natural thyroid drugs in the last ten years. Some of the reasons practitioners are turning to natural thyroid include:
•Their patients are on levothyroxine drugs, and are still suffering obvious thyroid symptoms such as loss of eyebrow hair, swelling, slow reflexes, etc.
•Their patients were on natural thyroid in the past, and reported greater energy and improved quality of life that they don’t have now on levothyroxine.
•The doctors prefer natural or bio-identical hormones, rather than synthetic hormones.
•The doctors have found in their practice that their patients in general tend to respond better to the natural thyroid when compared to synthetic.
Unfortunately, many doctors aren’t willing to explore hypothyroidism treatment options with their patients. These doctors instead offer only levothyroxine, and refuse to prescribe natural desiccated thyroid drugs.
This is the heart of the controversy.
Conventional doctors believe that levothyroxine is the best – and only – option for treatment.
Open-minded doctors, however, believe that levothyroxine is just one option for treatment. These practitioners believe that some older and less expensive drugs are equally – if not more – effective than newer, more expensive drugs. These practitioners are guided not by what is most “modern,” but rather, by what is most effective in safely restoring their patients to good health.
Some practitioners, in fact, prefer to prescribe desiccated thyroid after comparing the results of synthetic versus natural thyroid in their patients, because they believe patients are more likely to feel better on a natural drug.
Ultimately, one size fits all doesn’t work in thyroid treatment. The best thyroid medicine is the one that works best, and safely, for each patient. Figuring out which drug that is, and what dosage is best for you, means you and your practitioner must work together in a trial and error process to discover the best treatment for you.
The overriding message for thyroid patients is: Know your treatment options. Make sure that you have a practitioner who not only recognizes the importance of considering all your options, but one who is willing to work in a partnership to find safe, effective treatment.
Mary Shomon is an internationally-known thyroid patient advocate, and is author of a number of best-selling health books, including Living Well With Hypothyroidism and The Thyroid Diet. Since 1997, she has run the Internet’s most popular thyroid patient sites: Thyroid Site  and
(June 2006) 

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