TRβ, or thyroid hormone receptor beta, is a protein that binds to thyroid hormones, which are crucial for regulating metabolism, growth, and development in the body. It plays a significant role in mediating the effects of these hormones in various tissues, influencing processes such as heart rate, body temperature, and energy levels. There are two main types of thyroid hormone receptors: TRα and TRβ. While TRα is primarily involved in heart and brain functions, TRβ is more prevalent in the liver and pituitary gland. Dysregulation of TRβ can lead to various health issues, including hypothyroidism and hyperthyroidism.