Potassium Iodide: Radiation Protection, Benefits, & Side Effects

Potassium Iodide: Radiation Protection, Benefits, & Side Effects

Potassium Iodide is a white, odorless chemical compound made up of 76% iodine and 23% potassium. You might also see it represented by its chemical formula, KI: K for potassium and I for iodine. As a supplement, KI exists in tablet or liquid form. Potassium iodide’s most well-known use is in radiation emergencies when it’s taken to flood out the radioactive iodine with a stable, safe iodine form. Healthcare providers also use potassium iodine during surgeries or as a topical skin treatment, and individuals may use it as a nutritional supplement and for detoxing. However, KI is not the ideal form of iodine for some of these uses.

Why Is Iodine Important?

Iodine plays a crucial role in metabolism, hormone balance, immune system health, and mental health. The greatest concentration of iodine is in your thyroid, but your muscles, brain, salivary glands, and skin also require it. Iodine is especially important to women’s health as it’s an important building block of hormones produced in the ovaries.

Iodine is critically important during fetal and child development. Thus, all pregnant women should be conscious of their iodine intake. Severe cases of prenatal iodine deficiency can lead to stunted physical and mental development and deafness.[1]

What Is the Difference Between Iodine & Iodide?

Iodine, iodide, and potassium iodide are all different forms of the chemical element iodine. Elemental iodine falls within the halogen group on the periodic table of elements. Elemental iodine occurs as I2 – two molecules bonded together. Iodide is the ionic form of iodine — in other words, one iodine molecule.The halogen group also includes chlorine, fluorine, and bromine or chloride, fluoride, and bromide in the ionic form.

The term iodide means iodine in an ionic state (I-), in this case, a negative ion (i.e., anion) because it has a free electron. The term iodide is also used when an iodine ion is bonded to another element, such as sodium iodide or potassium iodide. Potassium iodide exists as a white salt, which makes it easy to add to table salt. When potassium iodide is consumed, your body converts the iodide into useful iodine.

Thirty-seven forms of iodine exist, but only one occurs in nature (I-127). The radioactive forms of iodine are created through chemical reactions and have short half-lives, which means they decay into other forms quickly — but not before causing damage to people near it. Radioactive iodine-131 is formed when uranium decays in nuclear reactors. I-131 is also the form of iodine you’d be exposed to during a nuclear disaster, and for which potassium iodide would protect you.

What Is Potassium Iodide Used For?

There are five primary uses for potassium iodide.

Protection From Radiation Exposure

A concentrated form of potassium iodide is the preferred treatment post-radiation exposure for preventing the thyroid uptaking the radioactive form of iodine (I-131). The KI saturates the thyroid gland, preventing other forms of iodine for entering for 24 hours. The dose should be repeated once daily until the threat is gone.[2]

According to the U.S. Food & Drug Administration (FDA), the amount of potassium iodide that should be taken in response to a radiological disaster is as follows:[2, 3]

Age Dosage
18+: 130mg
Pregnant or Lactating Women: 130mg
Children 3- 18 months: 65 mg
Children 1 month – 3 years: 32 mg, delivered via KI oral solution
Infants birth – 1 month: 16 mg, delivered via KI oral solution

Potassium iodide only protects for 24 hours, so depending on the situation, it may be necessary to take more than one dose. It depends entirely on how long the risk persists.

Preparation for Thyroid Surgery

Physicians may use a saturated solution of potassium iodide or SSKI to prepare patients for surgical removal of the thyroid gland. They believe this helps reduce blood loss and stabilizes thyroid function during the delicate process.[4, 5]

Nutritional Support for the Thyroid

People also use lower amounts of potassium iodide as a dietary supplement to boost iodine levels. In 1924, authorities around the world began supplementing table salt with KI to prevent iodine deficiencies, creating “iodized salt.” At the time, people living in inland, landlocked areas had less access to iodine-rich seafood, and the soil that grew vegetables in these inland regions was low since most iodine originates in the sea. Potassium iodide can be used as a supplement to boost iodine levels. In hyperthyroid conditions, it is used to slow or calm thyroid function.[6] When the body produces too much thyroxine, a thyroid hormone, it uses up the body’s iodine (which is part of the thyroxine) leading to a deficiency.

Topical Skin Therapy

Research suggests potassium iodide has antifungal properties[7] and can soothe skin redness and swelling.[8] Since 1900, potassium iodide has been used to treat serious fungal skin infections like sporotrichosis and several others.[9] Potassium iodide works as well as a pharmaceutical drug for the treatment of these conditions.[10]

Supporting Respiratory Health

Some respiratory conditions produce excess mucus that can harden in the airways and make breathing difficult. A saturated solution potassium iodide or SSKI is sometimes used as an expectorant to break-up mucus in the chest and throat.[4] While it works quite well, it should be used under a doctor’s supervision.


Some people use potassium iodide or other iodine supplements to detox their bodies. Saturating the thyroid with iodine can prompt the release of undesirable halogens (including chloride and fluoride) from the thyroid. It can also purge the system of toxic metals since iodine binds to such elements in the body. For therapeutic use of KI in non-radiation scenarios, talk to your health care provider, as your serving will vary depending on your use and personal health history.

Does Potassium Iodide Have Side Effects?

While iodine is a safe and vital nutrient, some people believe they have allergic reactions to iodine. The truth is that a person cannot be truly allergic to iodine itself. Some people experience hypersensitivity reactions or allergies to substances containing iodine but the reaction is caused by something else, such as povidine in a povidine-iodine antiseptic solution, allergy to proteins within seafood, sensitivity to iodine-containing radiocontrast dye, or possibly an allergy to the KI combination. Having an allergy to shellfish or iodine-based contrast dyes does not mean one will be allergic to potassium iodide.

According to the FDA, mild side effects of KI at the higher doses used for radiation therapy may include skin rashes, swelling of the salivary glands, and iodism which causes a metallic taste in the mouth or burning throat. A mild reaction to KI may produce red, itching skin, nausea, and vomiting, while more severe reaction can lead to swelling of the face and throat and difficulty breathing.[3] Should any symptoms occur after taking iodine, seek medical attention.

Some studies found that potassium iodide worsened the skin condition dermatitis herpetiformis, often associated with gluten sensitivity.[11] Likewise, individuals with Hashimoto’s thyroiditis or Graves disease should discuss iodine supplements with their healthcare provider. With Hashimoto’s disease, the body attacks and destroys the thyroid gland, and it is typically treated with replacement thyroid hormones. In Grave’s disease, the body over-produces thyroid hormones. Research has suggested that supplemental iodine has negative impacts on both of these conditions.[12, 13]

Potassium Iodide & Radiation

The infamous 1986 Chernobyl nuclear explosion caused massive amounts of radioactive iodine and xenon gas to be released into Poland, Russia, and other parts of Europe. In the immediate aftermath, Polish authorities distributed potassium iodide to nearly 7 million adults and 10.5 million children 16 and younger.[14] One dose of potassium iodide saturates the thyroid with stable iodine, thus preventing the absorption of radioactive Iodine-131 and instead promoting its quick passing from the body.

The action by Polish authorities protected the nation’s citizens. In contrast, Belarus and Ukraine did not supply their population with potassium iodide. Those regions saw thyroid cancer in children jump 30 to 60-fold the previous levels in the first four years after the disaster, and up to 100-fold in the following years.[14, 15]

Because of the success of potassium iodide for radiation therapy immediately after Chernobyl, Japanese authorities distributed potassium iodide following the 2011 Fukushima Daiichi nuclear accident — and demand for it led manufacturers to run out.[15] Even Tokyo, which lies about 140 miles south of Fukushima, recorded radioactive iodine in the air.[15]

The protection potassium iodide offers makes it one of the World Health Organization’s essential medicines for high radiation exposures, which — fortunately — are exceedingly rare.[16]

However, the U.S. Food & Drug Administration (FDA) recommends local government agencies keep potassium iodide supplies on hand for similar unpredictable scenarios.[14]

And many people choose to keep potassium iodide pills or an alternative iodine supplement readily available.

Who Should Take Iodine Supplements?

  • People with iodine deficiency
  • People at risk of iodine deficiency
  • Pregnant women
  • Women of childbearing age
  • Children
  • People with various conditions for whom iodine can help

The World Health Organization (WHO) suggested that as many as one-third of the world’s population is at risk of iodine deficiency — that’s more than 2 billion people.[17]

Because iodine is so critical during fetal development, the American Academy of Pediatrics Council on Environmental Health (AAP) recommends pregnant women should take iodine to ensure healthy brain development of the growing baby.[18]

Since half of the pregnancies in the U.S. are unplanned, AAP recommends all women of childbearing age –– particularly ones actively trying to get pregnant –– note these recommendations. They estimated that only 15% of women consumed an adequate amount of iodine. Studies have linked higher miscarriage rates in pregnant women who did not take iodine supplements or who are iodine-deficient.[19, 20]

What Are the Symptoms of Iodine Deficiency?

A few common symptoms of mild iodine deficiency include fatigue, brain fog, memory lapses, and weight gain. More serious conditions can include hypothyroidism and goiter — a cyst growing on the thyroid gland.

Fortunately, adding iodine to the diet is easy. Shellfish and seafood, as well as sea vegetables like seaweed, are robust dietary sources of dietary iodine, though there are many others. Of course, if you choose to eat fish, choose varieties that don’t contain a lot of mercury, such as salmon, catfish, or flounder. Sea vegetables may also contain mercury or other impurities. Depending on your need, iodine supplements may be an easier solution, particularly if you don’t like seafood or you eat a plant-based diet, which we recommend.

Can You Get Too Much Iodine?

Yes, you can take too much iodine. The human body needs iodine for thyroid health, metabolism, and energy. And an increasing number of people are iodine-deficient by far, compared with iodine-saturated. However, some studies have found that too much iodine can lead to similar symptoms as iodine deficiency, including goiter and hypothyroidism.[21]

Repeated exposure to high amounts of iodine can lead to an iodine overdose, but this is exceedingly rare, and more of a risk for children.

References (21) [+]
  1. Melse-Boonstra A, Mackenzie I. "Iodine deficiency, thyroid function and hearing deficit: a review." Nutr Res Rev. 2013;26(2), 110-7. Accessed 14 Mar. 2018.
  2. "Frequently Asked Questions on Potassium Iodide (KI)." 14 Oct 2016. Accessed 14 Mar. 2018.
  3. "Potassium Iodide (KI) Preparation and Dosing Instructions for Use During a Nuclear Emergency." 22 Aug 2012. Accessed 14 Mar. 2018.
  4. "SSKI- potassium iodide solution." Upsher-Smith Laboratories, LLC. nih.gov. Accessed 14 Mar.
  5. Shinall MC Jr, et al. "Is potassium iodide solution necessary before total thyroidectomy for Graves disease?" Ann Surg Oncol. 2013;20(9), 2964-7. Accessed 14 Mar. 2018.
  6. "Potassium Iodide (By mouth)." PubMed Health.
  7. Urabe H, Nagashima T. "Mechanism Of Antifungal Action Of Potassium Iodide On Sporotrichosis." Int J Dermatol 8(1), 36-39.Accessed 14 Mar.
  8. "Potassium Iodide." American Osteopathic College of Dermatology.
  9. Sterling JB, Heymann WR. "Potassium iodide in dermatology: a 19th century drug for the 21st century-uses, pharmacology, adverse effects, and contraindications." J Am Acad Dermatol. 2000;43(4), 691-7. Accessed 14 Mar. 2018.
  10. Costa RO, et al. "Use of potassium iodide in Dermatology: updates on an old drug." An Bras Dermatol. 2013;88(3), 396-402. Accessed 14 Mar. 2018.
  11. Katz KA, et al. "Dermatitis herpetiformis flare associated with use of triidomethane (Iodoform) packing strips for alveolar osteitis." J Am Acad Dermatol. 2009; 60(2), 352–353.
  12. "Graves Disease." National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health. Accessed 26 Apr. 2018.
  13. "Hashimoto's Disease." National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health. Accessed 26 Apr. 2018.
  14. "Guidance: Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies." FDA.gov. Dec 2001. Accessed 14 Mar. 2018.
  15. Greenemeier L. "Does Potassium Iodide Protect People from Radiation Leaks?" Scientific American. 15 Mar. 2011. Accessed 14 Mar. 2018.
  16. "WHO Model List of Essential Medicines." United Nations, World Health Organization. Aug. 2017. Accessed 14 Mar. 2018.
  17. Andersson M, et al. "Iodine Deficiency in Europe: A continuing health problem." who.int. 2017. Accessed 14 Mar. 2018.
  18. "Iodine Deficiency, Pollutant Chemicals, and the Thyroid: New Information on an Old Problem." American Academy of Pediatrics Council on Environmental Health. Policy Statement. May 2014. Accessed 14 Mar. 2018.
  19. Grant JM. "Iodine deficiency and reproductive failure." BJOG: An International Journal of Obsetetrics and Gynaecology. 2000; 107(5):viii.
  20. Ziskra J, et al. "Iodine status in women after early miscarriages in the Czech Republic." ePoster. Endocrine Abstracts: 15th European Congress of Endocrinology. 2013. Accessed 14 Mar. 2018.
  21. Leung AM, Braverman LE. "Consequences of excess iodine." Nat Rev Endocrinol. 2014;10(3):136-142. Accessed 14 Mar. 2018.
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