More US Doctors Prescribing T3 for Hypothyroidism

by Mary Shomon Patient Advocate

If you are being treated for hypothyroidism, new research offers some potentially promising news on your treatment options. A survey published in late 2018 in the journal Thyroid reported that, when compared to physicians in other countries, physicians in North America are more likely to add T3 (Cytomel, liothyronine) to conventional T4/levothyroxine hypothyroidism treatment, and to prescribe natural desiccated thyroid (NDT) drugs.

This research represents a departure from current American Thyroid Association (ATA) guidelines for hypothyroidism treatment, last updated in 2014, which recommend prescribing generic or brand-name levothyroxine drugs. These guidelines have been quite clear that combination T4/T3 therapy is almost never needed or recommended, and they strongly recommend against NDT.

The survey findings

The researchers surveyed 389 respondents who treat hypothyroidism, and this number represented around 20 percent of the ATA membership. Among those surveyed, 86 percent were endocrinologists.

The survey recipients were given 13 different patient scenarios, with different descriptions of symptoms, low T3 test levels, or the presence of a genetic mutation known as a D2 deiodinase polymorphism. (This polymorphism makes it more difficult for a thyroid patient to convert T4 to T3, the active thyroid hormone.)

The physicians surveyed were asked to choose among treatment options that included:

  • Levothyroxine (T4) only — (In the United States it’s available as generic levothyroxine and brand names, including Synthroid, Levoxyl, Tirosint, and Unithroid)

  • Combination therapy where the levothyroxine dosage is dropped, and T3 added in the form of generic liothyronine or brand name Cytomel

  • Combination therapy where the levothyroxine dosage stays the same, and T3 is added

  • Natural desiccated thyroid drugs (generic NP Thyroid, Nature-throid, Thyroid WP, and Armour thyroid)

  • T3-only treatment (known as “monotherapy”)

Overall, around one-third of the physicians surveyed were willing to prescribe treatments other than T4-only therapy, a level that is higher than other regions studied.

The physicians surveyed were also more likely to add T3 to levothyroxine therapy, prescribe NDT, and prescribe T3 monotherapy.

Specifically, among those surveyed:

  • From 18 to 41 percent were willing to add T3 to levothyroxine, and reduce the levothyroxine dose

  • From nine to 29 percent were willing to add T3 and keep the current dose of levothyroxine

  • Less than 6.5 percent were willing to switch a patient to NDT

  • Less than one percent were willing to prescribe T3 monotherapy

A shift in attitude

Overall, these findings suggest a shift in a more open-minded attitude on the part of endocrinologists. Back in 2013, a survey of almost 900 endocrinologists found that less than one percent prescribed combination T4/T3 treatment, and only 3.6 percent were willing to even consider the approach.

The new survey found that in just four years, from 18 to 41 percent of the physicians surveyed were — depending on a patient’s circumstances and symptoms — willing to add T3 (and reduce the levothyroxine) dose. Between nine and 29 percent were willing to add T3 to the current levothyroxine dose.

Interestingly, the study also suggests that younger physicians are less likely to prescribe the T4/T3 combination therapies, compared to older doctors with more experience and years of practice.

What's driving this shift in prescribing practice?

According to the research, the increased prescribing of combination T4/T3 treatment is most likely due to patient requests. As the study states: "The authors speculate that the trend to prescribe combination therapy more frequently may be due to a desire to accommodate patient preferences and consider patient-centered outcomes." It’s apparently not related to any new research or evidence, as only one clinical trial on T3 was conducted since 2009, and the results didn’t favor the use of T3.

HealthCentral reached out via email to one of the study’s authors, endocrinologist Jacqueline Jonklaas, M.D, Ph.D. for some additional perspective. Dr. Jonklaas is an assistant professor at Georgetown University Medical Center.

“I think that we are seeing physicians consider prescribing T3-containing therapies more frequently for multiple reasons,” Dr. Jonklaas said. “The analysis we published in November 2018 suggested that the most powerful influence on physician prescribing was patient symptoms. Other influential patient-related factors, aside from the lab work up, were the presence of a polymorphism and a patient request for T3-containing therapy.”

Are we likely to see this trend continuing, with more physicians willing to consider prescribing therapies that include T3?

“I am not sure we can really assess trends very accurately, as the previous studies were conducted a little differently,” Dr. Jonklaas said. “However, it definitely appears to be a big change compared with prior data. Also, we have an upcoming analysis that suggests a slight upswing in prescribing of T3 therapies in December 2017 compared with Spring 2017.”

The view from integrative physicians

We reached out to several nationally-known integrative physicians who have years of experience treating patients with hypothyroidism. Both were somewhat underwhelmed and surprised by the findings.

Kent Holtorf, M.D., is an integrative physician and researcher, and medical director/founder of the national Holtorf Medical Group. He has several decades of specialized treatment of patients with hypothyroidism and manages a network of clinics around the country that treat thousands of patients with underactive thyroid conditions.

Dr. Holtorf told us by email:

“I would be encouraged if these findings were accurate, but I'm dubious of the conclusions.

The first survey focused on endocrinologists, and the second survey of ‘physicians’ was far broader. I'd be interested in whether there is actually a change in prescribing decisions from endocrinologists. I suspect there isn't.

I suspect there isn't a large increase by endocrinologists in the use of thyroid replacement therapies that include T3. The endocrinology community tends to bypass the latest evidence-based findings, and instead relies on medical society consensus and guidelines statements, which are considered the worst level of evidence by the World Health Organization and every other legitimate evidence-based ranking system.

I have published three review articles with hundreds of references showing straight T4 replacement is an inferior treatment for a large percentage of patients, especially if they have any chronic illness such as depression, diabetes, inflammation, or heart disease, for example.”

David Borenstein, M.D., an integrative physician in New York City and founder of Manhattan Integrative Medicine, had these thoughts about the findings.

“It's encouraging to hear that a third of doctors are willing to consider adding T3 to levothyroxine (T4) therapy for hypothyroidism. As a physician who has used T3 with patients for years, however, it's a surprise to me that this number isn't higher. All physicians treating hypothyroidism should at least consider whether a patient might benefit from added T3.

We now know that genetic differences, nutritional imbalances, and many other factors affect an individual's ability to convert T4 into T3 — the active thyroid hormone. Study after study has shown that the majority of patients has better symptom relief with the addition of T3. As long as patients are not overmedicated and there are no other contraindications, we owe it to our patients to consider T3 along with the other safe and effective treatment options for hypothyroidism.”

Your next steps

If you are hypothyroid and are still experiencing unresolved symptoms, your treatment may not be optimal. You should raise the question of whether you need and could benefit from T3 treatment with your physician directly. Start by outlining your unrelieved symptoms and explain that you would like T3 to be considered as an option. As seen in the study, patient symptoms and requests are driving factors in a doctor’s willingness to consider T3 treatment.

You may also want to ask for testing your free T3 levels, and/or genetic testing to determine if you have the polymorphism that makes it harder to convert T4 to T3. In both cases, test results can help support your physician’s decision to add T3 to your hypothyroidism treatment.

If your physician is unwilling to discuss the option of T3, you may want to find another physician. Keep in mind that the research shows that older, more experienced physicians are more likely to consider treating your hypothyroidism with more than levothyroxine, as compared to younger doctors.

A caution: If your doctor is careful about prescribing combination therapy, there’s a good reason. There are some circumstances when adding T3 may be a potential risk. These include:

  • Older patients

  • Patients with heart disease or a history of heart arrythmias

  • Patients with low bone density or osteoporosis

  • Pregnant women with hypothyroidism. (The increased thyroid hormone dosage given to pregnant women is typically given in the form of T4, because T3 does not easily cross the placenta and reach the developing baby.)

Mary Shomon
Meet Our Writer
Mary Shomon

Mary Shomon is a patient advocate and New York Times bestselling author who empowers readers with information on thyroid and autoimmune disease, diabetes, weight loss and hormonal health from an integrative perspective. Mary has been a leading force advocating for more effective, patient-centered hormonal healthcare. Mary also co-stars in PBS’ Healthy Hormones TV series. Mary also serves on HealthCentral’s Health Advocates Advisory Board.