Alert: Due to rapidly depleting worldwide stock, we are limiting customers to a maximum of 20 units each.

USA 🇺🇸 2-3 days (USPS from Texas) • UK 🇬🇧 1-2 days (Royal Mail from London) • EU 🇪🇺 5-7 days (from Germany)


ThyBlock™ Potassium Iodide Tablets


Warning: Due to current events, worldwide stock of potassium iodide is extremely low so we are limiting customers to no more than 20 bottles per order.

ThyBlock™ Pure Potassium Iodide tablets are a leading and effective treatment for blocking radiation absorption by the thyroid gland.

  • Lab-tested Pharmaceutical-grade Potassium Iodide
  • Priority Shipping available at checkout
  • FDA-Approved medical supplier
  • The world-standard treatment for nuclear radiation exposure
  • Multi-Year Shelf Life

IMPORTANT: We have three warehouses. Your order will ship domestically, regardless of whether you are ordering to/from the US, the UK, or the EU. Shipping times are updated daily and shown at the top of this page. Prices are displayed in USD (US dollars) regardless of your location at all times, but will be converted into your local currency at the fair google “spot” conversion rate immediately before billing your credit card or other payment method. To check current conversion rates, simply check Google.

Stock: 18 units

Out of stock



How Does Potassium Iodide (KI) Work?

The thyroid gland cannot tell the difference between non-radioactive and radioactive iodine. It will absorb both kinds. KI works by keeping radioactive iodine out of the thyroid gland where it can cause damage.

When a person takes KI, the thyroid absorbs the non-radioactive iodine in the medicine. Because KI contains so much non-radioactive iodine, the thyroid becomes “full” and cannot absorb any more iodine—either stable or radioactive—for the next 24 hours.

(Source: CDC)

Thyroid Wth / Without Potassium Iodide

30 Day Money Back Guarantee as Standard, Secure SSL Checkout

Your order is backed by a 30-day money back guarantee. If you are not satisfied with the service you receive from us, simply contact our support team for a full refund.

All order placed via our website are secured by 256bit encrypted SSL secure connection. Your data is never shared and your credit card details are never stored on our servers.


Free Shipping Throughout the United States & Continental Europe

All orders within the Continental USA and Continental Europe will ship with free priority shipping with tracking codes delivered via email.

We endeavour to dispatch all orders within 24 hours of them being placed, however during peak periods this may extend to 48 hours.


What is Potassium Iodide (KI)?

Potassium iodide (KI) is a type of iodine that is not radioactive and can be used to help block one type of radioactive material, radioactive iodine (I-131), from being absorbed by the thyroid.

In some radiation emergencies, usually nuclear power plant accidents, radioactive iodine may be released into the environment and enter the body through breathing or eating it. This is known as internal contamination. When the thyroid absorbs high levels of radioactive iodine, it can increase the risk of thyroid cancer in infants, children, and young adults many years after exposure. The thyroid is a gland in the neck that plays an important role in many body functions.

(Source: CDC)

Most Recent Reviews:

Quick delivery despite shortages
Aileen S • Today
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Ordered 2 days ago and the package arrived today despite the worldwide shortage. I have not consumed this product to date. I hope there is no need in the future. I purchased it to keep on hand. Great value.
A MUST HAVE for every 'Grab Bag'
Jason T • Today
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Look, if you're going to prepare for the worst, these are a MUST HAVE for your grab bag. They'll keep you and your family safe if the time ever comes
Could only order 20 packs
Steve B • Yesterday
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I had to make 3 separate orders to get the quantity I want (stocking up for my whole family) I know that these tablets are in high demand right now, but I hope the 20-per-customer limit will be removed in future. On a positive note all 3 shipments arrived quickly.
High quality
Lance P • Yesterday
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I'm ex-military and take these things seriously. I have a home test-kit (and im a bit of a chem nerd) so i was curious to test these. The quality is very high and I am comfortable trusting these in my med bag.
Brand new!
Gemma Y • 2 days ago
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I recently bought some potassium iodine from a seller on Amazon and found that the stock they sent me expired in less than 2 months! So I was very happy to see the production date on the thyblock bottle was just a few weeks ago and that they are shelf stable for years. Great experience ordering.
Customer service
Adam M • 2 days ago
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I needed to make a bulk order (corporate industry) and was very satisfied with the experience and how far ThyBlock went to meet my needs.
Power station
Thomas A • 2 days ago
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I recently moved near to a power station and given the stories on the news, i figured ordering some "just in case" was the smart thing to do. Package arrived quickly and the tracking number made it easy to get my delivery.
For emergency storage
Grant K • 3 days ago
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I don't think we can be too careful right now given the global uncertainty. I bought a dozen packs for my family and I - just for emergency storage

How Potassium Iodide (KI) Protects the Thyroid

KI and radioactive iodine are both types of iodine. They are both absorbed by the thyroid. For KI to work, a person must take it before or shortly after exposure to radioactive iodine. When a person takes the right amount of KI at the right time, it can help block the thyroid from absorbing radioactive iodine. This happens because the thyroid has already absorbed the KI, and there is no room to absorb the radioactive iodine. Think of filling a jar with blue marbles. If you then pour green marbles over the jar, there will not be room and they will just spill out. (Source: CDC)

What You Need to Know:

  • In a radiation emergency, some people may be told to take potassium iodide (KI) to protect their thyroid.
  • Do not take KI unless instructed by public health or emergency response officials or a healthcare provider.
  • There are limits to who should use KI and how much it can help. It only protects the thyroid from radioactive iodine (I-131) and does not protect other parts of the body from other types of radiation.
  • KI is recommended only for people under 40 and pregnant or breastfeeding people. Doses recommended by the U.S. FDA depend on age.
  • KI can have harmful health effects, especially if not needed or not taken correctly. If you are instructed to take KI, only use KI products that are approved by the U.S. FDA.

(Source: CDC)

ThyBlock is not FDA-approved for nuclear fallout. Only products that are FDA-approved may be legally marketed in the United States for this purpose. Only three brands of drugs are currently FDA approved for this purpose, and in times of possible crisis there may be no stock available of these brands. ThyBlock is a dietary supplement marketed for general thyroid health and cellular defense, not for the particular purpose of protecting you from nuclear fallout, and ThyBlock is not a drug. The FDA does not have an approval process for dietary supplements.

The information on this page, which has been sourced from the CDC and made available here in the interest of public health, is for informational purposes only. Where certain dietary supplements contain the same active ingredient and/or dosage as an FDA-approved drug, the FDA’s approval of said drug should not be misconstrued as an approval of, or recommendation for, the similar dietary supplement.

As is the case with all dietary supplements sold in the USA, ThyBlock is not intended to diagnose, treat, or prevent any disease. ThyBlock is also not FDA-approved, as the FDA does not approve dietary supplements in the USA (the FDA approves drugs and medical devices).


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