β3, or beta-3 adrenergic receptor, is a type of protein found in the body that plays a role in regulating metabolism and energy expenditure. It is primarily located in adipose (fat) tissue and the bladder. When activated, β3 receptors can help increase the breakdown of fat and improve insulin sensitivity, making them a target for obesity and diabetes treatments. Research has shown that stimulating β3 receptors can enhance thermogenesis, the process by which the body generates heat and burns calories. This has led to interest in developing drugs that can selectively activate these receptors, potentially aiding in weight loss and metabolic health.