FDA Instructions for Making Lugol’s 5% Iodine

Source: https://www.fda.gov/food/laboratory-methods-food/bam-r40-lugols-iodine-solution

January 2001

Potassium iodide (KI)10 g
Iodine5 g
Distilled water100 ml

Dissolve KI in about 20-30 ml of distilled water. Add iodine and heat gently with constant mixing until iodine is dissolved. Dilute to 100 ml with distilled water. Store in amber glass-stoppered bottle in the dark.

Original Source: Bacteriological Analytical Manual, 8th Edition, Revision A, 1998.

But Jason, where do I get potassium iodide crystals, and iodine pellets?

I’m glad you asked. I usually buy them at amazon.com. I could provide links, and I will, but links break as products get sold out.

Here is Potassium Iodide 100 grams, 99.98% pure, for $19.94. The purity is as pure as things get. It’s both pharmaceutical grade, and food grade, the purest grade they make, the purest grade you can buy.

Here are iodine crystals.

Please don’t tell me they are sold out. Instead, find another source, and give me the link in the comments below. It’s out there, and now you know what to search for.


  1. Or in English. 4 and 1/4 cups of water, 2 teaspoons of iodine, 100 grams of Potassium Iodide.

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