Which hormone is predominantly responsible for lowering blood glucose levels?

Insulin plays a crucial role in regulating blood glucose levels by promoting the uptake of glucose into cells, particularly in muscle and adipose (fat) tissue. When blood glucose levels rise, such as after eating a meal, the pancreas secretes insulin. This hormone facilitates the movement of glucose from the bloodstream into cells where it can be used for energy or stored as glycogen in the liver and muscle tissue.

In addition to increasing glucose uptake, insulin also inhibits gluconeogenesis (the production of glucose from non-carbohydrate sources) and the breakdown of fat (lipolysis) in adipose tissue, further contributing to its blood-glucose-lowering effect. Due to these multiple mechanisms of action, insulin is the predominant hormone responsible for decreasing blood glucose levels in the body.