Iodide is a form of iodine that carries a slightly different atomic charge and normally is chemically bound with an element of potassium or sodium. While many people use the words iodine and iodide interchangeably, that is not exactly correct. An iodine atom will not possess the negative one charge that is found with an iodide ion. In addition, there are some applications for iodine that are not suited for iodide, and vice versa.

There are a number of different iodide compounds that are in use for a number of purposes. Hydrogen iodide and potassium iodide are two examples of iodide ions that can be used in antioxidant applications. Sodium iodide can help in the preservation of tissues and similar materials. Other forms of iodide include silver iodide, nitrogen iodide, and carbon iodide. Many of these variations are naturally occurring, but can also be created in a laboratory as well.

One medical application of iodide ions is in the treatment of hyperactive thyroids. Essentially, the ion can aid in blocking the release of excess thyroid hormone into the bloodstream, thus helping to curb symptoms such as anxiety and nervous agitation. However, it should be noted that the use of iodide in this application is seldom conducted as a stand-alone treatment. Because hyperthyroidism normally manifests a number of different symptoms, iodide is usually one ingredient in medications that address the task of managing symptoms and restoring a balance to the production of thyroid hormones. In addition, some modern thyroid treatments forego the use of iodide altogether, noting that the blocking effect may backfire once treatments are discontinued.

Iodide is a naturally occurring substance that appears throughout nature. One of the richest portions of the environment with iodide are the oceans. Algae is an excellent source of iodide. The cells of the algae require some type of protective coating in order to thrive. Iodide is one of the components that help to provide that protection. Plankton also serves as a rich depository of iodide, along with containing selenium and various fatty acids.