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Medical · Formula · Book recipe 6.2

Thyroid blocking with Lugol's iodine (radiation exposure)

Saturating your thyroid with stable iodine before or shortly after a nuclear release prevents your thyroid from absorbing radioactive iodine.

Handle with careWorks without power

How it works

Radioiodine alertauthorities call thyroid block
Dose by age/size40 / 20 / 10 / 5 drops
In water or juiceonce every 24 hours
Thyroid saturatedblocks I-131 uptake
Earlier is far more protectivebest within hours of exposure
KI tablets are FDA-approveduse Lugol's only when KI is unavailable

Quick facts

ADULT ≥154 lb
40 drops / 24 h
Age 3-18
20 drops / 24 h
AGE 1 mo-3 yr
10 drops / 24 h
Under 1 mo
5 drops once
When
KI unavailable

Hazard

Use only when authorities call for thyroid blocking, not for radiation in general. FDA approves KI tablets, not Lugol's. Avoid with iodine allergy.

I-131 is a fission byproduct from reactor failures and nuclear detonations; the thyroid absorbs it like iodine. FDA-approved KI tablets are the official countermeasure. After Chernobyl, Poland gave Lugol's iodine to over 17 million people; Nauman & Wolff (Am J Med 1993) found 40-62% thyroid-dose reduction in children dosed 1-4 days after exposure. Earlier is markedly more protective. Drop counts here match FDA targets at 2% Lugol's; if your bottle is 5%, use 16, 8, 4, and 2 drops for the same age groups. Use only when KI is unavailable.

What you'll need

  • Lugol's Iodine Solution (2% concentration) in amber glass with tight cap
  • Clean water or juice (for dilution and ingestion)
  • Calibrated dropper or graduated syringe (for accurate dosing)

Steps

  1. Adults and adolescents at least 154 lbs: 40 drops (about 2 mL) once every 24 hours while authorities indicate radioiodine exposure is ongoing. Adults over 40 rarely need it and should take it only if emergency officials specifically direct them to, since their risk of radioiodine thyroid cancer is low.
  2. Children and adolescents 3-18 not yet at adult size (under 154 lbs): 20 drops (about 1 mL) once every 24 hours.
  3. Children 1 month to 3 years: 10 drops (about 0.5 mL) once every 24 hours.
  4. Newborns under 1 month: 5 drops (about 0.25 mL) as a single dose. Pregnant or breastfeeding women: 40 drops as a single dose; repeat only with medical guidance if exposure persists and no other protection is available, since repeats can suppress thyroid function in the fetus or infant. Have any newborn who receives KI checked by a pediatrician for thyroid function.

Warnings

Take only when authorities call for thyroid blocking, for radioiodine exposure, not radiation in general. The FDA approves KI tablets, not Lugol's. Stop and seek care for rash, facial swelling, or palpitations. Avoid if you have iodine allergy, dermatitis herpetiformis, or hypocomplementemic vasculitis. With thyroid disease, consult a physician. Confirm your bottle's strength before dosing: 2% and 5% Lugol's need different drop counts.

Storage and shelf life

Unopened: 5 to 10 years in cool, dark, sealed conditions. After opening: shelf life varies by storage and manufacturer (commonly 12-18 months); replace if color fades, crystals form, or potency drops. Best container: amber glass, tightly sealed; HDPE plastic is acceptable. Avoid clear glass and reactive metals (aluminum, copper, plain steel). See the Containers section.

Questions this answers

Tap a question for the short answer.

Can I use lugol's iodine instead of potassium iodide tablets?

Only when KI tablets are unavailable. After Chernobyl, Poland gave Lugol's iodine to over 17 million people, and a 1993 study found a 40 to 62% thyroid-dose reduction in children dosed 1 to 4 days after exposure. KI tablets remain the official countermeasure.

How many drops of lugol's iodine for radiation protection?

With 2% Lugol's, adults at least 154 lbs take 40 drops every 24 hours, ages 3 to 18 under that weight take 20, ages 1 month to 3 years take 10, and newborns get 5 drops once. With a 5% bottle, use 16, 8, 4, and 2 drops for the same groups.

How do I protect my thyroid from nuclear fallout?

Saturate your thyroid with stable iodine before or shortly after a release so it cannot absorb radioactive iodine. KI tablets are the official countermeasure, and Lugol's iodine is the fallback when KI is unavailable. Earlier dosing is markedly more protective. Take it only when authorities call for thyroid blocking.

What is the lugol's iodine dose for children in a nuclear event?

Using 2% Lugol's, children and adolescents 3 to 18 who are under 154 lbs take 20 drops, about 1 mL, once every 24 hours. Children 1 month to 3 years take 10 drops, about 0.5 mL. Newborns under 1 month get 5 drops as a single dose.

How long does lugol's iodine last?

Unopened, it lasts 5 to 10 years in cool, dark, sealed conditions. After opening, shelf life varies by storage and manufacturer, commonly 12 to 18 months. Replace it if the color fades, crystals form, or potency drops. Amber glass with a tight seal is the best container.

How long do I take iodine during radiation exposure?

Take one dose every 24 hours for as long as authorities indicate radioiodine exposure is ongoing. Newborns under 1 month and pregnant or breastfeeding women take a single dose, and repeat only with medical guidance. Adults over 40 rarely need it at all.

Keep going

Read nextPotassium iodide (KI) tablets for nuclear emergenciesWhat potassium iodide tablets do, which nuclear events call for them, when to take them, who needs them most, shelf life, and Rob's tablet pick.Medical · Supply

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Medical · FormulaSource: Prepper's Chemical Survival Guide, Recipe 6.2, p. 28 · Last reviewed 2026-09-18

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