Which hormone is known as the "hunger hormone" that stimulates appetite?

Ghrelin is often referred to as the "hunger hormone" because it plays a crucial role in stimulating appetite and regulating energy balance. Produced primarily in the stomach, ghrelin levels rise just before meals, signaling to the brain that it is time to eat. Once food is consumed, ghrelin levels decrease, which helps to signal fullness and reduce appetite. This hormone acts on the hypothalamus, a region in the brain responsible for hunger and energy expenditure, by promoting feelings of hunger and increasing food intake.

Understanding ghrelin's function is particularly important in the context of weight management and appetite regulation. For individuals experiencing obesity or other eating disorders, the ghrelin signaling pathway may be disrupted, leading to increased appetite and challenges in maintaining a healthy weight. In contrast, other hormones, such as leptin (which tells the brain to stop eating), play opposing roles in appetite regulation. Hence, while leptin, insulin, and lipoprotein lipase all play roles in energy utilization and storage, ghrelin's distinct function in activating hunger differentiates it as the key "hunger hormone."