ERβ, or Estrogen Receptor Beta, is a protein that plays a crucial role in the body's response to estrogen, a key hormone involved in various physiological processes. It is one of two main types of estrogen receptors, the other being ERα. ERβ is found in various tissues, including the brain, bones, and reproductive organs, and helps regulate functions such as cell growth, differentiation, and metabolism. Research has shown that ERβ may have protective effects against certain diseases, including some types of cancer and cardiovascular conditions. Its activation can influence gene expression and cellular signaling pathways, making it an important target for understanding hormone-related health issues and developing potential therapies.