Lugol's Iodine (5%)Wat is Lugols Iodine? Lugol's Iodine is a classic solution of iodine and potassium iodide in purified water. This formula was developed as early as the 19th century by the French physician Jean Lugol and has since been known for its simplicity and stability. Our variant contains 5% iodine and 10% potassium iodide in 85% purified water and comes in a dark glass bottle with pipette cap for precise dosing. What makes Lugol's Iodine special? Timeless