The label I saw said that it contained 5 mg molecular iodine, 5 mg sodium iodide, and 2.5 mg potassium iodide (product by Terry Naturally, EuroPharma). I'm not sure why you think there's only 2 mg iodine. The part that confuses me is whether they mean there's a total of 7.5 mg iodide, or whether the list is correct as written. If so, the actual iodide content would be less than 7.5 mg, due to the need to account for the sodium and potassium.