Thyroid hormone is a crucial substance produced by the thyroid gland, located in the neck. It plays a vital role in regulating the body's metabolism, which is how our body converts food into energy. This hormone affects many bodily functions, including heart rate, temperature control, and even how quickly we burn calories. There are two main types of thyroid hormones: thyroxine (T4) and triiodothyronine (T3). These hormones work together to ensure that our body's systems function properly. When the levels of thyroid hormones are balanced, we feel energetic and healthy, but imbalances can lead to conditions like hypothyroidism or hyperthyroidism.