How to Perform the Iodine Patch Test


Iodine is one of the building blocks the thyroid uses to produce the hormones necessary for proper metabolic function. As you might guess, without enough iodine, you can experience a number of problems, such as hypothyroidism. There’s a quick and easy way to tell if you’re iodine deficient, the iodine patch test. The Iodine Patch Test simply measures how quickly the body absorbs iodine through the skin.

What is the Iodine Patch Test?

The iodine patch test measures how quickly your body absorbs iodine. The steps to perform it are relatively simple:

Get a solution or tincture of iodine (the orange solution, not the clear one.

Paint a 3-inch by 3-inch square on your abdomen, inner thigh or inner forearm. Allow it to dry before touching anything, as it will stain.

Monitor the patch over the next 24 hours for color changes.

The thing to pay attention to is how long it takes for the iodine patch to disappear. If the patch still exists 24 hours later, the results are normal. If the patch disappears or mostly disappears in less than 24 hours, it may indicate some degree of deficiency. In fact, significant lightening or disappearance in less than 18 hours could indicate moderate to severe iodine deficiency and suggest a need for supplemental iodine.

Things to Remember

There are a few things to keep in mind. Make sure you use an iodine solution made for application to the skin. Although several recent studies have demonstrated increases in iodine levels through skin absorption suggesting the result of this test may reflect a deficiency or adequacy of iodine, remember that this is a home test and the results shouldn’t be interpreted as an iron clad diagnosis. [1] [2] [3] Supplementing your diet or nutritional regimen with iodine may be something to think about.

To learn more about iodine, check out the video for my webinar, Everything You Need to Know About Iodine.

– Dr. Edward F. Group III, DC, ND, DACBN, DCBCN, DABFM


Miller KL, Coen PE, White WJ, Hurst WJ, Achey BE, Lang CM. Effectiveness of skin absorption of tincture of I in blocking radioiodine from the human thyroid gland. Health Phys. 1989 Jun;56(6):911-4.
Zimmermann MB, Crill CM. Iodine in enteral and parenteral nutrition. Best Pract Res Clin Endocrinol Metab. 2010 Feb;24(1):143-58. doi: 10.1016/j.beem.2009.09.003.
Tomoda C, Kitano H, Uruno T, Takamura Y, Ito Y, Miya A, Kobayashi K, Matsuzuka F, Amino N, Kuma K, Miyauchi A. Transcutaneous iodine absorption in adult patients with thyroid cancer disinfected with povidone-iodine at operation. Thyroid. 2005 Jun;15(6):600-3.

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