The thyroid gland sits at the front of the neck beneath the Adam’s apple. It comprises two lobes, which wrap around the windpipe in a butterfly shape. The thyroid absorbs iodine from the diet to produce hormones that regulate metabolism. The main hormones are T3 and T4. These hormones regulate the speed at which food is broken down and converted to energy. They also influence body temperature, weight, blood pressure, heart rate, energy levels and mood.