Protecting Your Thyroid From Radiation

Nuclear Power Plant at Sunset
Christophe Van Biesen/Moment/Getty

Every time there is a nuclear reactor accident somewhere in the world, there is a panicked rush to buy up every single potassium iodide tablet in the United States. This happens because a frightened public is trying to protect against their thyroid glands against risks from the possible toxic radioactive plume that could pass over the United States.

Nuclear plants can release radioactive iodine, which can damage the thyroid gland, increasing the risk of hypothyroidism and thyroid cancer. Radioactive iodine is especially risky to infants, children, and unborn babies. 

If you live downwind of a nuclear plant, experts recommend that you do keep enough potassium iodide on hand for your entire family, just to be prepared in the unlikely event of a nuclear accident or attack on the nearby nuclear facility. (But you should only take the potassium iodide if instructed to by authorities.) 

Let's take a look at ten things you should know about protecting your thyroid from radiation.

1. All potassium iodide can do is protect your thyroid gland from being damaged by one radioactive isotope: radioactive iodine. Radioactive iodine is NOT an "Armageddon pill" or a "radiation protector pill." When taken properly, potassium iodide can saturate your thyroid with iodine, and prevent it from absorbing radioactive iodine. This in turn can prevent the increased risk of thyroid cancer associated with radiation exposure.

2. To take potassium iodide properly, you must take it in the proper form. This means you should have a potassium iodide, an iodide/iodine combination that is considered most effective. You also need to take the potassium iodide at the proper time. That means you need to take the radioactive iodide in the hours before and after a radioactive plume is passing over your area. It is not effective if you take it in the days before or after. You also can risk your health if you take potassium iodide at the wrong time, or without guidance from experts.

How much should you take, and when? These official guidelines from the experts will help:

3. If you have had Graves' disease and were already treated with radioactive iodine, potassium iodide is not necessary to protect your thyroid against radiation.

4. If you have had your thyroid surgically removed, potassium iodide is not necessary to protect your thyroid against radiation.

5. If you are not in an area downwind of a nuclear release or accident, the likelihood that you will need potassium iodide to protect your thyroid against radiation is VERY small.

6. Most experts have indicated that harmful levels of radiation from most international nuclear accidents such as Chernobyl and Fukushima don't reach the United States. For the radioactive iodine to be a risk to your thyroid gland, radioactive plumes would need be travel many thousands of miles, the radiation would need to remain intact and not be dispersed. This is very unlikely. 

7. In a radiation emergency, the risk of developing thyroid cancer is thought to justify the risk of taking potassium iodide. But if you are not directly in the path of the radioactive plume, potassium iodide will not only not protect you from anything, it MAY INCREASE your risk of developing thyroid problems. Let's be clear about this. Potassium iodide can trigger or worsen hypothyroidism and hyperthyroidism, worsen existing thyroid conditions, cause conditions such as the Jod-Basedow phenomena, and the Wolff-Chaikoff effect, and ultimately cause temporary or even permanent thyroid conditions. It can also cause sialadenitis (an inflammation of the salivary gland), gastrointestinal disturbances, allergic reactions and rashes.

8. There are three FDA-approved forms of potassium iodide: Iosat Tablets (130 mg), ThyroSafe Tablets (65 mg) and ThyroShield Solution (65 mg/ml.)

9. Don't pay more than $20 to $30 for a bottle or package of potassium iodide tablets..

10. There are nuclear reactors located across America (See a map from the Nuclear Regulatory Commission showing where they are located.) To protect us against any future radiation emergencies that could affect you locally, you may want to have potassium iodide on hand as part of your family emergency kit. 

A Word from Verywell

Potassium iodide is available without a prescription.  But remember, as a preventative measure, it should be taken only when you are instructed to by authorities during a nuclear emergency. Also, remember that it works best when taken within 3 to 4 hours of exposure to radioactive iodine. 

Was this page helpful?
Article Sources
  • Centers for Disease Control and Prevention. "CDC Radiation Emergencies | Facts About Potassium Iodide (KI)." August 2015.