Which hormone is primarily responsible for stimulating hunger?

The hormone primarily responsible for stimulating hunger is ghrelin. Ghrelin is often referred to as the "hunger hormone" because it plays a significant role in regulating appetite and energy balance in the body. It is produced mainly in the stomach and secreted when the stomach is empty, signaling the brain to induce the sensation of hunger. This process encourages eating and helps to regulate body weight by stimulating food intake.

Ghrelin levels typically increase before meals and decrease after eating, making it a key player in the short-term regulation of food intake. Understanding how ghrelin functions can provide insight into various conditions related to appetite and weight management. In contrast, other hormones mentioned, such as leptin, which is involved in signaling satiety, and insulin, which regulates glucose levels, are not primarily involved in stimulating hunger but rather in telling the body when it has had enough to eat. Cortisol, often associated with stress, can influence appetite but is not the core hormone that signals hunger directly.