Yes, it is essential to do your research before simply taking anything. Thank you for adding this word of caution. Iodine can indeed be harmful in large doses, especially to those with thyroid problems. However, this is why it is essential to use detoxified iodine. It provides a different chemical delivery than normal iodine.
Still, read up on it before taking it. This is also why you are to start with one drop in a glass of water. That is such a minuscule amount that it is very safe.