Easy method of analysing iodine content in supplements? Most health-food stores carry supplements supposedly containing iodine for people with iodine deficiency. I recently bought some kelp tablets that are supposed to have iodine but as a consumer how can I be sure that there is any iodine in them at all, let alone the claimed minimum daily requirement.

How do I know that I'm not just taking green-colored sawdust? Is there a cheap way to test a kelp tablet for its iodine content? If not are there testing labs that I could send some kelp to for testing that isn't going to cost me thousands of dollars?
Take some potato starch dissolved in water (you can easily get it from the water when you boil potatoes), and put a tablet into the water. If the water becomes bluish black, there is iodine in the tablet.

Yes, there are testing labs that will determine the amount of iodine in the tablets which will cost somewhere around \$100 to \$200.