How to Choose a Medication for Thyroid Disease

Understand your options and the research behind them

Man comparing medications
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If you have thyroid disease, you may be wondering what the best thyroid medication is. Though there are several options, unfortunately, there isn't an easy, cut-and-dry answer.

Thyroid Medication Options

Many thyroid patients who require thyroid hormone replacement to treat their hypothyroidism do not realize or are never told that there is more than one medication available. You can read a more detailed article about thyroid hormone replacement, but here's a quick overview:

  • Levothyroxine—a synthetic form of the T4 hormone—is the drug of choice for the mainstream and conventional medical world. Commonly-known brands include Synthroid, Levoxyl, and Tirosint, and various generics from different manufacturers are also available. Many thyroid patients are only told about and offered levothyroxine, and many conventional physicians will prescribe only this drug for their hypothyroid patients.
  • Liothyronine—a synthetic form of the T3 hormone—is far less commonly prescribed by endocrinologists, but is more commonly used by integrative physicians and physicians with expertise in hormone balance. The brand names in the U.S. are Cytomel and Triostat, and a generic is also available. Many thyroid patients are never tested for Free T3 to determine if they're low in T3, the active thyroid hormone, except by hormone balance experts and integrative and/or naturopathic physicians.
  • Natural desiccated thyroid—also known as NDT, "natural thyroid," "porcine thyroid," or derogatorily by some physicians as "pig thyroid"—is a prescription drug derived from the dried thyroid glands of pigs. Common brands are Armour Thyroid and Nature-throid, and a generic is also available. Most endocrinologists and many mainstream physicians do not support or prescribe the use of natural desiccated thyroid drugs, though the American Thyroid Association (ATA) acknowledges that some patients respond well to NDT.

    What the Research Says

    Research doesn't offer a definitive answer. Some studies say that there are no proven benefits to the addition of T3 to levothyroxine (T4) therapy. Other studies, like the major Danish study published in the European Journal of Endocrinology, found that T4+T3 combination therapy was superior to T4/levothyroxine only treatment. Another study found that natural desiccated thyroid drugs were a safe and effective alternative to levothyroxine, though they are not often prescribed.

    Bottom line? Until someone does a huge, flawless, double-blind, crossover, peer-reviewed study looking at safety, effectiveness, and symptom relief of levothyroxine, levothyroxine plus liothyronine, and natural desiccated thyroid—and publishes the results in a major medical journal—we won't have a definitive answer from the scientific point of view.

    Patients and Physicians Have Varying Preferences 

    As you can tell, the answer to the question of "What's the best thyroid medication?" will vary greatly, depending on who you're asking. If you ask conventional endocrinologists or read their official guidelines (often funded, not surprisingly, by drug companies), they almost universally recommend only levothyroxine—synthetic T4—to the exclusion of other options.

    Some of them even go so far as to tout one particular brand. If you ask holistic practitioners, a small subset feel strongly about using only natural desiccated thyroid drugs and not synthetic drugs. 

    The Best Thyroid Medication

    The best thyroid drug to treat hypothyroidism is the one that safely and best resolves the symptoms of each individual patient. In other words, one size does not fit all, and a drug that works perfectly for one patient may not work for others. Find the thyroid drug or drug combination that safely works best for you, and there's your answer: that's the best thyroid drug—for YOU.

    Sources:

    Hoang TD, Olsen CH, Mai VQ, Clyde PW,  Shakir MK.  Desiccated Thyroid Extract Compared With Levothyroxine in the Treatment of Hypothyroidism: a Randomized, Double-Blind, Crossover Study. The Journal of Clinical Endocrinology & Metabolism. May 2013;98(5):1982-90. doi: 10.1210/jc.2012-4107.

    McAninch EA, Bianco AC. The History and Future of Treatment of HypothyroidismAnnals of Internal Medicine. August 11, 2016;164(1):50-56. doi:10.7326/M15-1799.

    Nygaard B, Jensen EW, Kvetny J, Jarløv A, Faber J. Effect of Combination Therapy with Thyroxine (T4) and 3,5,3'-Triiodothyronine Versus T4 Monotherapy in Patients with Hypothyroidism, a Double-Blind, Randomised Cross-over StudyEuropean Journal of Endocrinology. December 2009;161(6):895-902.