Product Reviews
Potassium Iodide (KI) and Potassium Iodate (KIO3) Review Article: Radioprotective Agents

Initial Posting: 6/25/02  Updated: 3/18/11 Potassium Iodide and Potassium Iodate Seals of Approval

What It Is:
Potassium iodide (KI) and potassium iodate (KIO3) are compounds that can deliver usable, stable iodine to the body. Both forms can be equally effective but vary somewhat in taste and dosage (See ConsumerTips™: What to Consider when Buying for more information about the forms and brands).

What It Does:
As demonstrated following the Chernobyl nuclear reactor accident in 1986, iodine supplements can protect the thyroid gland from the effects of radioactive iodine released by such accidents, as well as from other nuclear events. It is an effective means by which to protect against the effects of radioactive iodine when evacuation, sheltering, or avoidance of contaminated food and milk cannot prevent exposure. KI and KIO3 cannot, however, protect against absorption of materials besides radioactive iodine.

Thyroid cancer rates have been reported to increase by as much as 100 fold in exposed populations, with malignancies beginning approximately four years after exposure. Children are particularly sensitive to radioactive iodine because their thyroid glands are very active. In fact, prophylaxis with stable iodine is recommended for children when even low doses of radiation are present, while adult prophylaxis is only recommended at higher levels of exposure. (See ConsumerTips™: What to Consider When Using for more information.)

Radioactive iodine released during a nuclear accident or explosion moves in the environment through the air and can be inhaled, making it most dangerous to individuals downwind of the accident or explosion. As it moves, it can also affect drinking water and exposed crops. Milk from animals grazing on exposed grasses is also affected and, in the Chernobyl incident, milk exposed many people to radioactive iodine who were not otherwise directly exposed. Iodine is needed by the thyroid gland to produce hormones. The iodine pills essentially saturate the thyroid gland with non-radioactive iodine and block the uptake of radioactive iodine. Stable iodine is most effective if taken a few hours prior to exposure but can be beneficial even if taken within three hours after exposure.

March 2011:
Due to concerns over potential radiation exposure arising from damaged Japanese nuclear reactors, many people have recently sought potassium iodide and potassium iodate products and information about them. To assist, we have updated the list of products originally provided in this report. Some are no longer sold or have been replaced with newer products. See the  Update and the revised table in the report to find out where products may be purchased and their availability as of 3/18/11.
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