Potassium iodide tablets: what they do and when to take them

What it actually protects

A nuclear accident can release radioactive iodine, which the body concentrates in the thyroid gland. Potassium iodide saturates that gland with stable iodine so it stops absorbing the radioactive form. That is its entire effect: it is not an antidote to radiation and does not reduce external exposure.

The main protective actions remain sheltering inside a building, shutting down outside ventilation, or evacuating when told to.

When to take it

Only when health or civil protection authorities instruct you, using the dose and timing they announce. Taking it too early, too late or without need reduces its benefit and adds unnecessary risk.

• Wait for the official instruction on emergency alerts, radio or television.
• Follow the age-based dose given; never improvise quantities.
• Do not take it 'just in case' because of a news report.

Who needs medical caution

The benefit is greatest for children, pregnant and breastfeeding people, and smallest for older adults. Some people should not take it or need supervision: iodine allergy, certain thyroid or kidney conditions, and some medications. Ask your doctor or pharmacist in advance, not during the emergency.

This guide is informational and does not replace professional medical advice or official instructions.

What you can prepare today

Know how you will receive official alerts, which room you would shelter in, and how to shut off ventilation. Keep several days of water, food and regular medication, and write down family health contacts on paper.

• Check that your phone can receive public emergency alerts.
• Identify the interior room easiest to seal.
• Keep a buffer of prescription medication.