Ghrelin is a 28-amino acid peptide hormone produced primarily by the stomach that serves as the endogenous ligand for the growth hormone secretagogue receptor (GHS-R1a). It is the only known circulating orexigenic (appetite-stimulating) hormone. Ghrelin stimulates growth hormone release, increases appetite, promotes fat storage, and coordinates energy metabolism between the gut and brain. It requires a unique post-translational modification (n-octanoylation at Ser3) for biological activity. Pharmaceutical analogs like anamorelin have been developed for cancer-related cachexia.
Category: Growth Hormone / Appetite. Evidence rating: B (meaningful human data).
Clinical status: Endogenous hormone. Analog anamorelin approved in Japan for cancer cachexia. Multiple analogs in clinical trials.
Ghrelin binds to the growth hormone secretagogue receptor type 1a (GHS-R1a) in the hypothalamic arcuate nucleus, activating NPY/AgRP neurons to stimulate appetite. The n-octanoyl modification at Ser3 is essential for receptor binding and is catalyzed by ghrelin O-acyltransferase (GOAT). GHS-R1a…
Safety considerations: As an endogenous hormone, ghrelin itself has a well-understood safety profile; Exogenous administration causes intense hunger, which may lead to unwanted weight gain; Water retention and facial edema reported with repeated administration.
Reviewed by the PeptideAtlas Editorial Team.
| Amino-acid sequence | GSS(octanoyl)FLSPEHQRVQQRKESKKPPAKLQPR |
|---|---|
| Molecular weight | ~3371 g/mol |
| Half-life | ~30 minutes (IV) |
| Production method | synthetic |
| Anti-doping status | Prohibited in sport (WADA) |
| US regulatory status | Not FDA-approved for exogenous use. Analog anamorelin not FDA-approved. Research compound only. |
No. Ghrelin is the endogenous hormone. GHRP-6, GHRP-2, hexarelin, and ipamorelin are synthetic growth hormone secretagogues that bind the same GHS-R1a receptor but are structurally distinct from ghrelin.
Native ghrelin has a half-life of only ~30 minutes and requires the acyl modification for activity. Synthetic analogs like anamorelin, macimorelin, and ipamorelin were developed to overcome these limitations with longer half-lives and oral bioavailability.
Yes. Ghrelin is the primary hunger hormone. Exogenous administration reliably increases appetite and food intake, which leads to weight gain in most contexts. This is therapeutically useful in cachexia but problematic for other applications.
Coverage on this site: Peptide Therapy for Weight Loss Record Includes FC Bayern Text, Ipamorelin Handling: Storage, Documentation, and Best Practices, Ipamorelin Stability: What Researchers Should Know, CJC-1295 and Ipamorelin Blend: Growth Hormone Research in Canada, Ipamorelin: Selective GH Secretagogue Research in Canada, Editorial Standards and Content Policy for Peptide Research.