Potassium iodide tablets: the FDA-approved KI products (2026)
Potassium iodide (KI) can block radioactive iodine from the thyroid in a nuclear emergency. The FDA lists the KI products it has approved for sale without a prescription, and this page lists only those, because many 'potassium iodide' tablets sold online are supplements, not approved products. CDC says to use only FDA-approved KI.
By Tom Calder · Updated October 24, 2026 · 2 products, prices indicative
All 2 compared
| Product | Strength | Count | FDA status | Price |
|---|---|---|---|---|
130 mg · 14 tablets · FDA-approved, no prescription FDA-approved KI for adults | 130 mg | 14 tablets | FDA-approved, no prescription | |
Our verdictOur verdictResearched iOSAT 130 mg tablets are on the FDA's list of approved potassium iodide products sold without a prescription. KI protects only the thyroid, and only from radioactive iodine. CDC says not to take it unless public health or emergency officials, or a healthcare provider, tell you to, and that it's recommended only for people under 40 and women who are pregnant or breastfeeding. Best for FDA-approved KI for adults Good
Worth knowing
Who shouldn't buy it: Don't buy it if you're over 40 and not pregnant or breastfeeding: CDC doesn't recommend KI for you. | ||||
65 mg · See the listing · FDA-approved, no prescription Smaller 65 mg tablets, easier to split for children | 65 mg | See the listing | FDA-approved, no prescription | |
Our verdictOur verdictResearched ThyroSafe 65 mg tablets are also on the FDA's approved, no-prescription list. The smaller strength makes dosing easier for children and teenagers, following CDC's dosing table and officials' instructions. Like any KI, take it only when told to. Best for Smaller 65 mg tablets, easier to split for children Good
Worth knowing
Who shouldn't buy it: Don't buy it if you won't follow official instructions in an emergency: KI isn't a general radiation shield. | ||||
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Before you buy
Buy only FDA-approved KI
The FDA lists iOSAT 130 mg and 65 mg tablets, ThyroSafe 65 mg tablets and a 65 mg/mL oral solution.
Strength: 130 mg tablets suit adults; 65 mg tablets make dosing children easier, following CDC's dosing table.
Check the expiration date and store as the label directs.
We verify every product's specifications against at least two independent sources, re-check its US price and stock on a schedule where we can track it automatically, and cross-check safety-relevant claims against official guidance. Every review is labeled Researched or Used and reviewed by us: where we've bought a product, or been sent it free, and used it ourselves, its review says which; where we haven't, our verdict is a considered spec-and-evidence comparison, not a hands-on test — and commissions never change a ranking either way. Read our full methodology →
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Common questions
Which potassium iodide is FDA-approved?
The FDA lists iOSAT 130 mg and 65 mg tablets, ThyroSafe 65 mg tablets and Potassium Iodide Oral Solution USP 65 mg/mL as approved and available without a prescription.
When should I take potassium iodide?
Only when officials or a healthcare provider tell you to. CDC says KI works best within 24 hours before or 4 hours after exposure.