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The T4/T3 Thyroid Drug Controversy

Thyroid Hormone Replacement With T4 and T3 Drugs Vs. Levothyroxine Alone


Updated June 18, 2014

The use of T4 and T3 together as a thyroid hormone replacement treatment for hypothyroidism -- an underactive thyroid -- is controversial, given that the standard treatment is levothyroxine (T4) alone. The addition of T3 to the levothyroxine/T4-only treatment is, however, a topic of ongoing research and discussion. This treatment controversy is explored in a number of articles here at the About.com Thyroid site.

T3 Drugs Improve Quality of Life

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A 1999 study reported in the New England Journal of Medicine found that patient quality of life was improved with the addition of T3 to levothyroxine therapy.

2003 JAMA Study Says T3 Offers No Benefit

The Journal of the American Medical Association (JAMA) reported on research that found no benefit to the addition of T3.

Dr. Ken Woliner Assesses the JAMA T4/T3 Study

Dr. Ken Woliner critiques the 2003 JAMA study and points out problems in the study, suggesting that T3 should not be ruled out based on the study's findings.

Dr. Ken Blanchard on the T4/T3 Issue

Dr. Ken Blanchard, MD, PhD, author of the book "What Your Doctor May Not Tell You About Hypothyroidism," critiques the 2003 JAMA study.

Jacob Teitelbaum, MD on the T4/T3 Issue

Chronic fatigue, fibromyalgia and metabolism expert Jacob Teitelbaum, MD has these criticial insights about the JAMA T4/T3 studies.

Study Compares T4 to T4/T3 Treatment

The results of trial published in the March 2005 Archives of Internal Medicine compared levothyroxine/T4 treatment for hypothyroidism, versus 2 different combinations of levothyroxine plus synthetic T3 (known as liothyronine).

T4/T3 Treatment Preferred by Patients in Study

The May 2005 issue of the Journal of Clinical Endocrinology and Metabolism reported on a study that showed that hypothyroidism patients preferred a combination T4/T3 treatment to T4-only treatment. The researchers also found that combination treatment is associated with weight loss, while T4-only treatment is not.

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