Skip to Content
View Additional Content In This Section
Thyroxine (T4) is the most common form of thyroid hormone that is
released by the thyroid gland. Once it reaches the tissues, it is converted to
another form of thyroid hormone called triiodothyronine (T3), which is more
active in regulating the body's chemical reactions.
In tests of thyroid function, a low T4 level may indicate the
presence of low thyroid levels (hypothyroidism). Certain forms of liver or
kidney disease may also cause a low T4 level, even though a thyroid problem may
not be present.
Current as of:
November 14, 2014
E. Gregory Thompson, MD - Internal Medicine & Matthew I. Kim, MD - Endocrinology
To learn more about Healthwise, visit Healthwise.org.
© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.