Ghrelin
An endogenous peptide hormone primarily produced in the stomach that stimulates appetite, promotes fat storage, and triggers growth hormone release from the pituitary.
Ghrelin is the body’s primary hunger signal and also acts as a natural growth hormone secretagogue — it binds to the growth hormone secretagogue receptor (GHS-R) to stimulate GH pulses from the pituitary. Synthetic GHRPs like GHRP-6 and GHRP-2 were designed to mimic ghrelin’s GH-releasing activity, often with greater potency and stability than ghrelin itself.
Beyond appetite and GH release, ghrelin has emerging roles in metabolic regulation, cardiovascular protection, and stress response. Research peptides that act on the ghrelin receptor pathway are studied for applications ranging from muscle preservation to metabolic disease, making ghrelin a central node in understanding GH secretagogue pharmacology.