hormone
Ghrelin
Ghrelin is a gut-derived peptide hormone involved in appetite signalling and growth-hormone release.
Educational draft · Human scientific and editorial review pending. About review status
The stomach is a major source; ghrelin levels and activity change with fasting, meals and circadian context.
How it works
A meal-related gut signal
Ghrelin is produced mainly in the stomach and acts through the growth-hormone secretagogue receptor. Its best-known physiological role is signalling hunger and coordinating energy homeostasis, while it also affects gastric motility and growth-hormone release.
Roles and processes
Ghrelin signals to Appetite regulation
Ghrelin is one gut-derived signal integrated by appetite-regulation circuits.
Evidence: Established · Source checked 2026-09-05 · Sources: NIH National Library of Medicine: Physiology, Appetite And Weight Regulation; NIH National Library of Medicine: Biochemistry, Ghrelin
Worth knowing
It has more than one form. Acylated and desacyl ghrelin circulate in different proportions, and the acylated form is the better characterised activator of the canonical receptor.
A closer look
“Hunger hormone” is shorthand
Ghrelin is one signal in a network that includes leptin, gut peptides, the nervous system and meal context.
Meal timing changes its signal
Ghrelin generally rises during fasting and before meals and falls after eating, with patterns shaped by meal and circadian context.
References
Source-checked local draft.
Human editorial review pending.