Before · 2 min read
Iodine tablets (potassium iodide) — the facts
What iodine tablets do and do not do, and why you should only take them when officials say so.
Draft: written from the official sources below, awaiting human review.
What they do
Potassium iodide (KI) fills the thyroid gland with safe iodine, so it cannot absorb radioactive iodine. It works best taken shortly before or just after exposure, and one dose protects for about 24 hours.
What they do not do
- They do not protect the rest of the body.
- They do not protect against other radioactive materials, or against the fallout after a nuclear explosion, which is the biggest danger.
- They are not a treatment for damage already done.
The best protection is still: get inside, stay inside, stay tuned.
When to take them
Only when public health or emergency officials, or your doctor, tell you to. They will say who should take it and whether a second dose is needed.
- Officials usually prioritise people under 40, and pregnant or breastfeeding women.
- Taking more than advised can cause severe illness or death.
- Some people (for example with iodine allergy or certain thyroid conditions) should not take it. Ask a doctor.
- Iodised salt, iodine-rich food and iodine supplements are not substitutes.
Rules and availability differ by country. See your country page for local guidance.
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