Carlyle Lugol's 2% Solution
Lugol’s solution used with proper context, or seaweeds such as nori and kelp flakes in food-style amounts.
Ingredients
Iodine 2%, potassium iodide 4%, distilled water 94%.
A US source in the Tested Swaps directory. Check that it ships to Europe; where it does not, the directory lists a European alternative alongside it.