Just remember; that it doesn't always is about Iodine / not iodine, when it comes to the thyroid. Read labels of whatever you put on the skin.
"Some of the chemicals have been implicated as causing thyroid problems. German researchers found that rats exposed to the sunscreen chemical 4MBC had raised levels of thyroid stimulating hormones and heavier thyroid glands. Another chemical, benzophenone 2, was found to alter thyroid hormone levels, although the effect was reversed by other chemicals present in sunscreens.