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What is Potassium Iodide (Please Don’t Say Radiation Pills)

What is Potassium Iodide (Please Don't Say Radiation Pills)
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Part of my job duties as a emergency planner involve training first responders in radiation safety. So after the Fukushima Nuclear plant emergency I was acutely aware of all the bad advice and rumors floating around about Potassium Iodide (KI).

Now that a lot of that fear has subsided, and we can talk about it objectively and without our eyes bulging out in fear, I want to take a second and talk about what KI actually does.

In the spirit of openness I want to say that I have some KI at my house, and since my in-laws live within 10 miles of a nuclear plant I gave them some also. But I have it out of an abundance of caution than fear. I doubt (and statistics bear it out) neither I nor my in-laws will ever have to use it.

Radioactivity, or the process of an element giving off radioactivity, is a chemical property of a material. Since it is a chemical property, it behaves in predicable manners and we can take precautions against its effects.

In order to survive your body needs certain things. Oxygen and water are the two basic things, but your body also needs chemical building blocks to perform a variety of biological processes. We get these through food. Just like we drink OJ when we are sick to get the vitamin C, or Milk for strong teeth and bones. We need iodide for proper production of thyroid hormones. These thyroid hormones are most closely linked with growth and mental development. Unfortunately not all people receive enough iodide to provide for their bodies’ needs. As a matter of fact, the land around the Great Lakes was known as the “goiter belt” because the soil is particular iodine-deficient, this resulted in higher incidence of goiter among residents. Luckily, iodized salt has almost entirely wiped out iodine deficiency in the U.S.

Since one of the isotopes of “fission products” created by nuclear fission (either in a reactor or in an explosion) is the radioactive form of iodine, it is possible that one of the radioactive products released in either a nuclear power plant disaster or in an attack using a nuclear weapon.

If a person is exposed to radioactive iodine, and their thyroid needs iodine, the body will absorb the radioactive iodine and deposit it in the thyroid. The body cannot distinguish between the radioactive and non-radioactive isotopes.

What KI does is fill the thyroid up with iodine. So if you take it BEFORE exposure to the radioactive iodine, it makes sure there is no room for your body to store the radioactive isotope. That way the bad stuff flows right out of your system as waste.

The problem is that KI is often sold as a “radiation pill”, so that people don’t know its specific use. It only protects against one chemical in a very specific way. It does nothing to prevent damage by radiological exposure, or contamination by materials other than radioactive iodine.

Some people are also allergic to KI, and while some people that are allergic to shellfish are also allergic to KI, it is possible to be allergic to one without the other, and since I am not a doctor, I am not capable of telling you what you are or aren’t allergic to. I would suggest that if you think exposure to radioactive iodine is something you would like to prepare for, you might ask your doctor to test to see if you are allergic to iodine.

You don’t have to be scared of radiation, but you do have to have a little knowledge and respect for what it can and cannot do.

Published inMedical & Sanitation


  1. harry harry

    I’m doing a little research on, a dose of radiation from a solar flare… I would appreciate your opinion thank you…Harry in KY..

    • Could you please be a little more specific, I did an article on EMP that has some info on CME, but it was not specific to the radiological aspect. General radiation information from Cosmic rays is pretty easy to find though.

  2. Alan Morris Alan Morris

    While what you have written is technically correct, it could also be dangerously misleading. Yes, it is true that KI “only protects against one chemical in a very specific way . It does nothing to prevent damage by radiological exposure, or contamination by materials other than radioactive iodine” are accurate statements; but they overlook that radioactive iodine (RAI) is the most dangerous product that might be relased in a power plant accident because RAI would, by far, affect the most people. In fact, about 95% of the known injuries from Chernobyl were RAI related. Further, while it is true that “some people are allergic to KI” the actual number who are allergic is very small. The US FDA estimates that the incidence of side effects from KI among the general population is as low as 1 in 10 million, and these are almost always mild and fully reversible.

    In practical matters, KI is the most valuable strategy for protection in a radiation emergency. To suggest otherwise could lead to thousands of thyoid cancers that could easily be prevented. This is why the government’s decision not to stockpile adequate amounts of KI could be a tragic mistake.

    For more information, see

    • I have spent the last three years working in public radiological protection. My main job was to instruct emergency workers on how to protect themselves and the public against radiological contamination as well as reducing their exposure.

      In my personal experience their is a lot of misinformation on what KI does, and have heard many people call KI a “radiation pill” – Heck it is even sold by less than scrupulous companies as a “radiation pill”. What my article is about is teaching what it is used for – that way people can spend their resources on items that protect them and not what makes them feel good.

      I don’t know about “the governments” decision not to stockpile adequate amounts of KI, because I don’t know what you think is adequate. I know they have bulk KI in the national strategic stockpile. My state in particular keeps bulk KI for 100% of the population around our reactors even though KI is not indicated for 100% of the population.

      I am not downplaying the threat of Radioactive Iodine, it is definitely a danger, however, we learned from Fukishima that the borated cooling water mitigates the iodine release. Up until this more recent disaster that was only a theoretical assumption. Fukuishima is a lot closer to an American plant in design than the graphite reactor of Chernobyl – Its like saying because a pinto got smashed by a bus, you need seat-belts in tanks.

      Lastly, the link you posted is for a company that sells KI, If you benefit from the sale of KI, it would only be fair to disclose that. For the record I am not against the private stocking of KI, actually, as long as the individual has an understand of what they are buying and feel the need, I applaud them buying KI in whatever form they choose.

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