Which hormone is primarily responsible for stimulating appetite?

Ghrelin is often referred to as the "hunger hormone" because it plays a crucial role in stimulating appetite. It is produced primarily in the stomach and signals the brain to increase food intake when the stomach is empty. As ghrelin levels rise before meals, they create the sensation of hunger. This intricate mechanism helps the body regulate energy balance by promoting the consumption of food when necessary.

In contrast, insulin is primarily involved in glucose metabolism and helps lower blood sugar levels after eating. Leptin, often called the "satiety hormone," is secreted by fat cells and works to inhibit hunger, providing signals to the brain that the body has enough energy stored. Cortisol, a stress hormone, can influence appetite but is not the primary hormone responsible for stimulating hunger. Its effects on appetite can vary, often increasing cravings for high-energy foods during stress rather than directly stimulating the desire to eat. Therefore, ghrelin stands out as the key hormone driving the hunger response.