Thyroid hormone metabolism involves the production, conversion, and breakdown of hormones primarily produced by the thyroid gland. The main hormones are thyroxine (T4) and triiodothyronine (T3). T4 is converted into the more active T3 in various tissues, including the liver and kidneys, which helps regulate metabolism, energy levels, and overall growth. The metabolism of these hormones is influenced by several factors, including iodine availability, which is essential for their synthesis. Once released into the bloodstream, thyroid hormones are transported by proteins and eventually metabolized by the liver and kidneys, where they are excreted as inactive forms.