Also known as Lenomorelin · the hunger hormone · acyl-ghrelin
The only hormone that makes you hungry — a stomach peptide, uniquely fatty-acid-modified, that drives appetite and also releases growth hormone.
Research refreshed
Ghrelin is a 28-amino-acid hormone made mainly in the stomach and best known as the body’s principal hunger signal — levels rise before meals and fall after eating. It is biochemically unusual: it requires an octanoyl (C8 fatty-acid) group attached to its third residue to be active, the only known hormone modified this way. Beyond appetite, ghrelin is a potent releaser of growth hormone, which links it to the secretagogue peptides elsewhere in this catalog.
Almost every appetite hormone tells you to stop eating; ghrelin is the one that tells you to start. Secreted by the stomach when it is empty, it rises in the run-up to a meal, drives the sensation of hunger through hypothalamic feeding circuits, and falls once you have eaten. That makes it the orexigenic counterweight to satiety hormones like leptin, amylin, and the incretins — and a natural target for the opposite therapeutic goal: stimulating appetite in wasting conditions.
Its defining oddity is chemical. Ghrelin is the only human hormone known to carry an O-acyl fatty-acid modification — an octanoyl group esterified to the serine at position 3 by a dedicated enzyme (ghrelin O-acyltransferase, GOAT). Without that fatty acid the peptide cannot activate its receptor. This makes the GOAT enzyme an unusual drug target and the acylation a defining feature of how the hormone is studied and measured (acyl- versus des-acyl ghrelin).
Ghrelin’s second action is on growth hormone: it is the endogenous ligand of the growth-hormone secretagogue receptor, the same receptor hit by synthetic GHRPs such as ipamorelin and hexarelin found elsewhere in this catalog — so ghrelin is, in effect, the natural template those drugs imitate. Therapeutically the interest runs toward appetite stimulation: ghrelin-receptor agonists (anamorelin, relamorelin) have been studied for cancer cachexia and gastroparesis, making the hunger hormone a candidate where too little appetite is the problem.
Agonist at the growth-hormone secretagogue receptor (GHSR-1a). The octanoyl modification (added by the enzyme GOAT) is required for receptor binding. Activation stimulates appetite via hypothalamic NPY/AgRP neurons and triggers growth-hormone release from the pituitary.
Behind every vial of Ghrelin is the same exacting pipeline every research peptide runs — but the chemistry plays out differently for this molecule. Here is how Ghrelin, specifically, is brought into being.
On paper, Ghrelin weighs in at roughly 3,370.9 daltons. Before a single bond is made, the target sequence, salt form, and purity threshold are written down as the contract the finished material must meet.
Ghrelin is built one protected residue at a time by solid-phase synthesis, each cycle a deprotection, a coupling, and a wash. It also carries fatty-acid acylation, an extra step beyond a plain chain that adds both capability and cost.
The crude mixture — Ghrelin plus its deletions and side products — is then separated on preparative HPLC, and where the cut is taken decides the difference between a genuinely pure peptide and a barely-passable one.
A real batch of Ghrelin proves itself: identity confirmed by mass spectrometry against its ~3,370.9 Da, purity read directly off an analytical HPLC trace, water and counterion content measured. That batch-specific certificate of analysis is the only honest way to know what is actually in a vial of Ghrelin — and a short, cold, accountable chain of custody is how that purity survives the trip to your bench.
The standout synthetic challenge in this class: activity requires an O-octanoyl ester on the Ser3 hydroxyl — the only such acylation among human hormones (installed biologically by ghrelin O-acyltransferase, GOAT). Standard solid-phase synthesis assembles the 28-mer, but installing and preserving the acid- and base-labile octanoyl ester demands orthogonal side-chain protection and a deliberately mild final deprotection/cleavage, since the unmodified by-product (des-acyl ghrelin) is inactive. The acylation is the purity-defining step, and acyl-vs-des-acyl ratio is the assay that matters most.
Don't judge a vial by its cake. A fluffy, good-looking lyophilized powder reflects bulking agents and freeze-drying parameters — not purity. Insist on a batch-specific certificate of analysis.
Recent clinical trials and publications mentioning Ghrelin, pulled automatically from ClinicalTrials.gov and PubMed and refreshed daily. Listings are unfiltered search results, not curated endorsements.
A stomach-derived hormone that is the body’s main hunger signal — it rises before meals to stimulate appetite and falls after eating. It also triggers growth-hormone release.
It is the only known human hormone that needs a fatty-acid (octanoyl) group attached to one of its residues to work. The enzyme that adds it, GOAT, is a distinctive potential drug target.
Ghrelin is the natural ligand of the growth-hormone secretagogue receptor — the same receptor that synthetic GHRPs like ipamorelin and hexarelin activate. Those drugs essentially mimic ghrelin’s growth-hormone action.
No — this is a research and educational reference, not dosing guidance.
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