The thyroid is a small, butterfly-shaped, two-lobed endocrine gland located in the front of the neck, just below the Adam's apple, resembling the letters U or H. Part of the endocrine system, the thyroid gland is responsible for the production of the hormones thyroxine and triiodothyronine.

The thyroid gland's main role is to control the metabolic rate, the speed at which the body converts the food it consumes into energy. Working with the T3 and T4 hormones it produces, it helps regulate your metabolism. Along with these hormones, the pituitary gland is also involved, telling the thyroid how much of these hormones the body needs.

Beyond metabolism, the thyroid contributes to the proper functioning of many processes, from how your heart beats to weight gain, cholesterol levels, and even menstrual cycles. When the thyroid malfunctions or experiences problems, it can lead to various thyroid diseases.

Common thyroid diseases include hyperthyroidism, hypothyroidism, goiter, and thyroid cancer. Hyperthyroidism is a condition where the thyroid is overactive, while hypothyroidism occurs when the thyroid gland is underactive. Thyroiditis, for example, is an inflammation of the thyroid gland.