Restricting Iodine May Treat Subclinical Hypothyroidism

salt shaker iodine thyroid
Restricting iodine may be a viable treatment for subclinical hypothyroidism in some patients.

We know that iodine, as an ingredient of thyroid hormone, is essential for healthy thyroid function. But too much iodine can also be a problem for thyroid patients. Some of these issues regarding iodine were discussed in my article, The Iodine Controversy: Too Much vs. Not Enough, and What It Does To Your Thyroid?

A 2014 study from Korean researchers set out to look at the effect of restricting iodine in subclinically hypothyroid people in an iodine-replete area (an area not known to have iodine deficiency.) The researchers also looked at the link between the Thyroid Stimulating Hormone (TSH) levels and iodine intake.

Following 3 to 6 months of iodine restriction, the TSH levels dropped (from 9.0 mU/L to 4.7), and Free T4 levels increased significantly.

The researchers concluded that if a patient is in an iodine replete area, restricting iodine may normalize or, at a minimum, decrease the TSH levels in subclinically hypothyroid patients, making it a treatment option. They also found that TSH levels are strongly linked to the iodine levels.

More Resources on Iodine and the Thyroid


Joung JY1, et. al. "Effect of iodine restriction on thyroid function in subclinical hypothyroid patients in an iodine-replete area: a long period observation in a large-scale cohort." Thyroid. 2014 Sep;24(9):1361-8. doi: 10.1089/thy.2014.0046. Epub 2014 Jun 30. Online

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