T4 (Thyroxine)

T4, or thyroxine, is a hormone produced by the thyroid gland, located in the neck. It plays a crucial role in regulating metabolism, which is how the body uses energy. T4 helps control various functions, including heart rate, body temperature, and weight management. It is essential for growth and development, especially in children. The body converts T4 into another hormone, T3, which is more active. Proper levels of T4 are vital for overall health, and imbalances can lead to conditions like hypothyroidism (too little) or hyperthyroidism (too much), affecting energy levels and various bodily functions.