The Truth About Potassium Iodide

The Truth About Potassium Iodide

During the melt down of the reactors in Japan in 2011 and again now, with North Korea threatening to send nuclear bombs our way, potassium iodide (chemical name is KI) has flown off the shelves. This may not be a good thing — or even necessary for everyone.

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What Potassium Iodide Does and Does Not Do

What KI does:

(I will use the KI abbreviation throughout for brevity.)

  • The thyroid gland cannot tell the different between stable iodine and radioactive iodine and will absorb both, for the next 24 hours..
  • KI floods the thyroid with stable iodine which blocks radioactive iodine from entering the thyroid. The thyroid gland is the most sensitive body part to radioactive iodine — KI only protects the thyroid.

What KI does not do:

  • It will not protect the body from other radioactive elements — only radioactive iodine (RI). If no RI is present, taking KI will not protect anything and could be harmful.
  • KI does not keep radioactive iodine from entering the body and cannot reverse the health effects caused by RI once the thyroid is damaged.
  • Iodized table salt does not contain enough KI to block RI from harming the thyroid.
  • KI may not give you 100% protection.
  • Protection will increase depending on these three factors:Time AFTER contamination: The sooner a person takes KI, the more time the thyroid will have to “fill up” with stable iodine.Absorption: The amount of stable iodine that gets to the thyroid depends on how fast KI is absorbed into the blood.Dose of radioactive iodine: Minimizing the total amount of radioactive iodine a person is exposed to will lower the amount of harmful radioactive iodine the thyroid can absorb.
  • Taking a stronger dose of KI (potassium iodide), or taking KI more often than recommended, does not offer more protection and can cause severe illness or death.

People should take KI (potassium iodide) only on the advice of public health or emergency management officials. There are health risks associated with taking KI.

Who can take KI (potassium iodide)?

The thyroid glands of a fetus and of an infant are most at risk of injury from radioactive iodine. Young children and people with low amounts of iodine in their thyroid are also at risk of thyroid injury.

Infants (including breast-fed infants)

Infants have the highest risk of getting thyroid cancer after being exposed to radioactive iodine. All infants, including breast-fed infants need to be given the dosage of KI (potassium iodide) recommended for infants.

  • Infants (particularly newborns) should receive a single dose of KI. More than a single dose may lead to later problems with normal development. Other protective measures should be used.
  • In cases where more than one dose is necessary, medical follow up may be necessary.


The U.S. Food and Drug Administration (FDA) recommends that all children internally contaminated with (or likely to be internally contaminated with) radioactive iodine take KI (potassium iodide), unless they have known allergies to iodine (contraindications).

Young Adults

The FDA recommends that young adults (between the ages of 18 and 40 years) internally contaminated with (or likely to be internally contaminated with) radioactive iodine take the recommended dose of KI (potassium iodide). Young adults are less sensitive to the effects of radioactive iodine than are children.

Pregnant Women

Because all forms of iodine cross the placenta, pregnant women should take KI (potassium iodide) to protect the growing fetus. Pregnant women should take only one dose of KI following internal contamination with (or likely internal contamination with) radioactive iodine.

Breastfeeding Women

Women who are breastfeeding should take only one dose of KI (potassium iodide) if they have been internally contaminated with (or are likely to be internally contaminated with) radioactive iodine. They should be prioritized to receive other protective action measures.


Adults older than 40 years should not take KI (potassium iodide) unless public health or emergency management officials say that contamination with a very large dose of radioactive iodine is expected.

  • Adults older than 40 years have the lowest chance of developing thyroid cancer or thyroid injury after contamination with radioactive iodine.
  • Adults older than 40 are more likely to have allergic reactions to or adverse effects from KI.


What is the dosage and how often should KI be taken?

There are two forms of KI: pills and liquid and two strengths, 130 milligram (mg) and 65 mg. 

According to the FDA, the following doses are appropriate to take after internal contamination with (or likely internal contamination with) radioactive iodine:

  • Newborns from birth to 1 month of age should be given 16 mg (¼ of a 65 mg tablet or ¼ mL of solution). This dose is for both nursing and non-nursing newborn infants.
  • Infants and children between 1 month and 3 years of age should take 32 mg (½ of a 65 mg tablet OR ½ mL of solution). This dose is for both nursing and non-nursing infants and children.
  • Children between 3 and 18 years of age should take 65 mg (one 65 mg tablet OR 1 mL of solution). Children who are adult size (greater than or equal to 150 pounds) should take the full adult dose, regardless of their age.
  • Adults should take 130 mg (one 130 mg tablet OR two 65 mg tablets OR two mL of solution).
  • Women who are breastfeeding should take the adult dose of 130 mg.


A single dose of KI protects the thyroid gland for 24 hours. A one-time dose at recommended levels is usually all that is needed to protect the thyroid gland.

If someone is exposed to RI for more than 24 hours, instructions from public health officials may tell you to take one dose of KI every 24 hours for a few days.

Avoid repeat dosing with KI for pregnant and breastfeeding women and newborn infants.

Who should NOT take potassium iodide?

Some people should not take KI because the risks outweigh the benefits. According to the FDA, the following people should not take KI:

  • Persons with known iodine sensitivity
  • Persons with allergies to iodine, iodide, and shellfish
  • Individuals with dermatitis herpetiformis and hypocomplementemic vasculitis
  • People with nodular thyroid with heart disease should not take KI.
  • Individuals with multinodular goiter, Graves’ disease, and autoimmune thyroiditis should be treated with caution — especially if dosing extends beyond a few days. Speak to your doctor, because KI could be deadly for you.

A seafood or shellfish allergy does not necessarily mean that you are allergic or hypersensitive to iodine, but extreme caution should be used, and you should have the supplies on hand to treat a life-threatening allergic reaction. Personally, I probably would not take KI if I had a seafood allergy. If you are not sure if you should take KI, consult your healthcare professional before a disaster ever occurs.

If your thyroid gland has been removed, you will not benefit from taking KI.


Be Aware of the Possible Side Affects of KI

Side effects may include stomach or gastrointestinal upset, allergic reactions, rashes, and inflammation of the salivary glands. Even if taken as recommended, KI can cause rare adverse health effects related to the thyroid gland. These effects are more likely if a person:

  • Takes a higher than recommended dose of KI
  • Takes the drug for several days
  • Has a pre-existing thyroid disease.

Newborn infants (less than 1 month old) who receive more than one dose of KI (potassium iodide) are at risk for developing a condition known as hypothyroidism (thyroid hormone levels that are too low). If not treated, hypothyroidism can cause brain damage.

  • Infants who receive more than a single dose of KI should have their thyroid hormone levels checked and monitored by a doctor.
  • Avoid repeat dosing of KI to newborns.

Where can you buy potassium iodide?

KI is available without a prescription at drug stores and preparedness stores. Because of the pretty strict rules for using it and the possible side effects, having some in your preparedness supplies is a good idea but should be used ONLY if necessary. You can purchase it here

Because of the current threats:

Anyone who watches the news on TV or the Internet lately is fully aware of the threats to our national security by North Korea and ISIS, as well as domestic terrorists. Because of North Korea's possible new ability to send their ICBMs into our country, we all know there are many preparations we need to accomplish if we are going to survive, should they actually make good on their threats — and I strongly believe we can survive.

If you seriously plan to survive, start by asking yourselves the needed questions, such as:

These are only some of the questions you should be asking yourself, but it is a start. Please don't put off getting prepared — our existence seems very precarious lately and deserves our immediate attention.


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What do you think?

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