Des-acyl Ghrelin (Unacylated Ghrelin)
The abundant unacylated form of ghrelin that often opposes it — blunting appetite and glycemic effects. An endogenous peptide, studied in trials, not an approved drug
Des-acyl ghrelin (DAG), also called unacylated ghrelin (UAG), is the quieter twin of the famous hunger hormone ghrelin. Both come from the same precursor protein, but ghrelin carries a fatty (octanoyl) group on its third amino acid that it needs to switch on its receptor, GHSR-1a; des-acyl ghrelin lacks that group. For years it was written off as an inactive breakdown product — yet it is actually far more abundant in blood than ghrelin, and it turns out to be a metabolically active peptide in its own right. Rather than driving appetite and blood sugar up the way ghrelin does, des-acyl ghrelin often does the opposite: it can blunt ghrelin's push on food intake, improve after-meal blood sugar, and it acts on muscle, heart and fat through binding sites that are not the classic ghrelin receptor and have not yet been identified. That opposing, glucose-improving profile has made it a drug lead — an engineered unacylated-ghrelin analog (AZP-531, livoletide) was tested in people, including a randomized trial in Prader-Willi syndrome. Des-acyl ghrelin itself is an endogenous peptide studied in research and trials; it is not an approved medicine.
No established human dose Details ↓
Recommended Dosing
No established human dose
Des-acyl ghrelin and its stabilized analog AZP-531 (livoletide) have been given to people only in research and clinical trials — for example AZP-531 by daily subcutaneous injection for 14 days in a Prader-Willi trial — not as an approved treatment. No regulator has approved des-acyl ghrelin or its analog, and no established therapeutic dose exists; the amounts used in trials and research do not constitute a dose to self-administer, so none is printed here as guidance.
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What is it?
Ghrelin, the stomach hormone that drives appetite and growth-hormone release, only works in its acylated form — a fatty octanoyl group attached to its third amino acid lets it activate its receptor, GHSR-1a. When that group is absent, the peptide is called des-acyl ghrelin, or unacylated ghrelin. Counter-intuitively, this unacylated form is the majority of ghrelin circulating in the blood, and for a long time it was assumed to be an inert leftover. That view has changed: des-acyl ghrelin is now recognized as a hormone in its own right, separate from acylated ghrelin and from obestatin, the other peptide made from the same precursor.
The defining feature of des-acyl ghrelin is that it often acts as a functional counterweight to ghrelin. In animals, injecting des-acyl ghrelin alongside ghrelin abolishes ghrelin's appetite-stimulating effect and damps the activation of appetite neurons in the hypothalamus, recruiting nesfatin-1 'satiety' neurons instead; on its own it does not drive feeding. In human metabolic studies it can suppress circulating acylated ghrelin and improve after-meal blood sugar, especially where acylated ghrelin is high — which is why it has been pursued as a treatment lead for obesity, diabetes and Prader-Willi syndrome.
Importantly, des-acyl ghrelin does not work through the classic ghrelin receptor GHSR-1a, which it barely binds. Studies in heart, muscle and fat cells show it has its own specific, high-affinity binding sites — distinct from ghrelin's — that have not yet been molecularly identified. Through these it produces effects of its own: in heart-muscle cells it changes glucose and fatty-acid handling differently from ghrelin and can even partly reverse ghrelin's actions, and in skeletal-muscle precursors both ghrelin and des-acyl ghrelin promote the cells to mature and fuse into muscle fibres.
Because of this opposing, glucose-friendly profile, des-acyl ghrelin became a drug lead. An engineered, stabilized unacylated-ghrelin analog, AZP-531 (livoletide), was taken into human trials: in a randomized, placebo-controlled study in people with Prader-Willi syndrome — a genetic disorder of relentless hunger — it was well tolerated and improved hyperphagia scores and reduced waist circumference and fat mass, though it did not change body weight. These findings put unacylated ghrelin among the more clinically advanced of the endogenous peptides, even though the native hormone itself is not an approved medicine.
Des-acyl ghrelin is an endogenous human peptide studied in research and in trials, not an approved drug. It, and its analog, have been given to people in research and clinical studies, but no regulator has approved any version, and material sold online as 'des-acyl ghrelin' or 'unacylated ghrelin' is an unregulated research chemical of unverified content. Nothing here is a dose or a therapy; this page records what the published science says about the peptide.
Mechanism of Action
Des-acyl ghrelin is the unacylated form of ghrelin that does not activate the classic ghrelin receptor GHSR-1a. It is metabolically active through distinct, unidentified binding sites, often opposing acylated ghrelin's effects on appetite and glucose, and acting on muscle, heart and fat.
Counterweight to ghrelin
Des-acyl ghrelin blunts ghrelin's appetite-stimulating effect and hypothalamic activation, recruiting nesfatin-1 satiety neurons (PMID 18938204), and can suppress acylated ghrelin and improve after-meal blood sugar in people (PMID 23652397).
A distinct, unidentified receptor
It barely activates GHSR-1a; instead it has its own specific binding sites in heart, muscle and other cells, molecularly unidentified, through which it changes glucose and fatty-acid handling and promotes muscle-cell differentiation (PMIDs 20410201, 17202410, 25107984).
A metabolic drug lead
Its glucose-improving, ghrelin-opposing profile made the unacylated-ghrelin analog AZP-531 (livoletide) a clinical candidate, tested in a randomized trial in Prader-Willi syndrome (PMID 29320575).
Published Research
These are studies of des-acyl (unacylated) ghrelin read from their PubMed abstracts on November 6, 2026. They include two reviews — on des-acyl ghrelin as a metabolically active peptide and on its receptors — a randomized human trial of the unacylated-ghrelin analog AZP-531 in Prader-Willi syndrome, a study of its distinct binding sites and metabolic effects in heart cells, an animal study of it inhibiting ghrelin's appetite effect, and a cell study of its action on muscle differentiation. Des-acyl ghrelin and its analog have been given to people in research and trials, but no approved therapeutic dose exists.
Des-acyl ghrelin: a metabolically active peptide
A review repositioning unacylated ghrelin (UAG / des-acyl ghrelin) from an 'inert degradation product' to an important hormone, separate from acylated ghrelin and obestatin. It appears to have its own receptor, can act as a potent functional inhibitor of ghrelin, can suppress acylated-ghrelin levels in obese diabetic people and improve after-meal blood sugar — making UAG or its analogs candidates for metabolic disorders such as diabetes, obesity and Prader-Willi syndrome.
Receptors for ghrelin and desacyl-ghrelin
A pharmacology review noting that the only molecularly identified ghrelin receptor is GHSR-1a, which unacylated ghrelin barely activates. It evaluates evidence for effects of ghrelin and desacyl-ghrelin that cannot be explained by GHSR-1a — effects seen where GHSR-1a is absent and effects mimicked by UAG — proposing novel, still-unidentified ghrelin-receptor-like and UAG-specific receptors underlying actions in fat, muscle, bone, heart, vessels and tumours.
AZP-531 (unacylated-ghrelin analog) RCT in Prader-Willi
A multicentre, randomized, double-blind, placebo-controlled trial of AZP-531 — a first-in-class unacylated-ghrelin analog — in 47 patients with Prader-Willi syndrome (a disorder of relentless hunger). Given by daily subcutaneous injection for 14 days it was well tolerated and significantly improved hyperphagia questionnaire scores and appetite, reduced waist circumference and fat mass, and lowered post-meal glucose, though body weight did not change — supporting unacylated ghrelin as a treatment strategy worth longer trials.
Des-acyl ghrelin has its own binding sites in heart cells
In cardiomyocytes, des-acyl ghrelin and ghrelin had opposing metabolic effects: des-acyl ghrelin increased medium-chain fatty-acid uptake and helped insulin move the GLUT4 glucose transporter, while ghrelin blunted insulin-stimulated glucose uptake and des-acyl ghrelin partly reversed that. The cells had two specific binding sites for des-acyl ghrelin that ghrelin did not recognize — direct evidence of distinct des-acyl-ghrelin receptors (a cell result).
Desacyl ghrelin inhibits ghrelin's appetite effect
In non-fasted rats, ghrelin injected into the abdomen raised food intake within 30 minutes; desacyl ghrelin given at the same time abolished that increase, while desacyl ghrelin alone did not change feeding. It also reduced ghrelin-induced neuronal activation in the hypothalamic arcuate nucleus and recruited nesfatin-1 'satiety' neurons — showing desacyl ghrelin curbs ghrelin-driven appetite (a preclinical result).
Ghrelin and des-acyl ghrelin promote muscle differentiation
In C2C12 skeletal-muscle precursor cells — which do not express the classic ghrelin receptor GHSR-1a — both ghrelin and des-acyl ghrelin drove the cells to stop proliferating, mature and fuse into multinucleated muscle fibres, acting through p38 signalling. The cells carried a shared high-affinity binding site recognized by both forms, pointing to a novel, unidentified receptor for ghrelin and des-acyl ghrelin (a cell-culture result).
No Established Human Dose
Des-acyl ghrelin and its stabilized analog AZP-531 (livoletide) have been given to people only in research and clinical trials — for example AZP-531 by daily subcutaneous injection for 14 days in a Prader-Willi trial — not as an approved treatment. No regulator has approved des-acyl ghrelin or its analog, and no established therapeutic dose exists; the amounts used in trials and research do not constitute a dose to self-administer, so none is printed here as guidance.
What this rests on: PMID 29320575, PMID 23652397, PMID 18938204.
Educational information, not medical advice. The doses on this page come from approved labels, published studies and, where no study exists, amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
Unknown: we hold no label and no published test that says what forms or vial sizes Des-acyl Ghrelin (Unacylated Ghrelin) is sold in. A vial's own label is a seller's claim, not a source.
Mixing a vial: a worked example
Unknown: no human dose of Des-acyl Ghrelin (Unacylated Ghrelin) has been established (see No Established Human Dose below), so there is no amount to work out. The reconstitution calculator does the arithmetic for any vial, water and dose.
Storage before and after mixing
Unknown: no label or published stability study on file says how to store Des-acyl Ghrelin (Unacylated Ghrelin), before or after mixing. The mixing guide sets out the general rules, with their sources: keep a mixed vial in the fridge, and use it promptly, as the bacteriostatic water label says of any drug dissolved in it. The 28 days often quoted is the limit for an opened multiple-dose vial from a manufacturer, an outer limit set for sterility, not a time a mixed solution has been shown to keep. Nobody has published how long Des-acyl Ghrelin (Unacylated Ghrelin) stays intact once mixed.
How it is taken
Unknown: with no established human dose, there is no established way of taking Des-acyl Ghrelin (Unacylated Ghrelin). What the human studies gave and how is set out under No Established Human Dose.
What to expect, and when
How long it stays in the body: a half-life of not established as an approved drug; an endogenous circulating peptide. After about five half-lives almost none is left.
When effects appear: unknown; no source on this page gives a time to effect for Des-acyl Ghrelin (Unacylated Ghrelin). Results reported in the studies are under Published Research.
Source: half-life: PMID 29320575.
Side effects, and when to stop or get help
From the Side Effects section: In the Prader-Willi trial, the unacylated-ghrelin analog AZP-531 was well tolerated over 14 days of daily subcutaneous injection (PMID 29320575) — a short investigational safety signal, not an established profile; In metabolic studies des-acyl ghrelin can lower acylated ghrelin and post-meal glucose (PMID 23652397) — a pharmacological effect to be aware of, not an approved use; It acts through unidentified receptors in heart, muscle and fat (PMIDs 20410201, 17202410), so effects beyond appetite and glucose are possible and not fully characterised; Material sold online as 'des-acyl ghrelin' or 'unacylated ghrelin' is an unregulated research chemical of unverified content and purity. Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Des-acyl Ghrelin (Unacylated Ghrelin). Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“Des-acyl ghrelin is an endogenous peptide; human safety data come from research studies and from trials of its analog AZP-531, not from approved use”).
Interactions
Unknown: a PubMed search for human interaction studies of Des-acyl Ghrelin (Unacylated Ghrelin) (reviewed 2026-11-06) found none. Unknown is not the same as safe to combine.
Every peptide's record, with its source: the interaction matrix.
Checking what you bought
Unknown: no published independent test of Des-acyl Ghrelin (Unacylated Ghrelin) products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: Research Chemical (Not approved: Drugs@FDA and the openFDA label endpoint hold no approval for des-acyl (unacylated) ghrelin or its analog AZP-531 (livoletide), searched November 6, 2026). Sport: Not on the 2026 List.
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
Des-acyl ghrelin is an endogenous peptide; human safety data come from research studies and from trials of its analog AZP-531, not from approved use. The points below reflect that status.
Contraindications & Cautions
Des-acyl ghrelin has no approved use and no label. These points reflect its endogenous, investigational status.
Legal Status
Des-acyl (unacylated) ghrelin is an endogenous human peptide studied as a research and investigational compound; it is not an approved drug in any country.
Frequently Asked Questions
?What is des-acyl ghrelin?
The unacylated form of the hormone ghrelin — the same 28-amino-acid peptide, but without the fatty octanoyl group that ghrelin needs to switch on its receptor GHSR-1a. It is the more abundant form in blood and is a metabolically active peptide in its own right.
?How is it different from ghrelin?
Ghrelin drives appetite, growth-hormone release and higher blood sugar through GHSR-1a. Des-acyl ghrelin barely touches that receptor and often does the opposite — blunting ghrelin's appetite effect and improving after-meal glucose (PMIDs 18938204, 23652397) — through distinct, unidentified binding sites.
?Is it a treatment?
Not an approved one. Its glucose-improving, appetite-curbing profile made it a drug lead: a stabilized analog, AZP-531 (livoletide), was tested in a randomized trial in Prader-Willi syndrome (PMID 29320575), but neither the analog nor the native peptide is approved.
?Is it available to buy?
Not as a medicine — des-acyl ghrelin and its analog are not approved anywhere. Material sold online as des-acyl or unacylated ghrelin is an unregulated research chemical. Grey Peptides lists no sellers and recommends no source; this page records the published science.
References
- [review] Delhanty PJ, et al. "Des-acyl ghrelin: a metabolically active peptide." Endocr Dev, 2013;25:112-21. PMID: 23652397.
- [review] Callaghan B, et al. "Novel and conventional receptors for ghrelin, desacyl-ghrelin, and pharmacologically related compounds." Pharmacol Rev, 2014;66(4):984-1001. PMID: 25107984.
- [rct] Allas S, et al. "AZP-531, an unacylated ghrelin analog, improves food-related behavior in patients with Prader-Willi syndrome: A randomized placebo-controlled trial." PLoS One, 2018;13(1):e0190849. PMID: 29320575.
- [mechanism] Lear PV, et al. "Des-acyl ghrelin has specific binding sites and different metabolic effects from ghrelin in cardiomyocytes." Endocrinology, 2010;151(7):3286-98. PMID: 20410201.
- [animal] Inhoff T, et al. "Desacyl ghrelin inhibits the orexigenic effect of peripherally injected ghrelin in rats." Peptides, 2008;29(12):2159-68. PMID: 18938204.
- [mechanism] Filigheddu N, et al. "Ghrelin and des-acyl ghrelin promote differentiation and fusion of C2C12 skeletal muscle cells." Mol Biol Cell, 2007;18(3):986-94. PMID: 17202410.
- [other] UniProt Q9UBU3 (GHRL_HUMAN), read November 6, 2026: des-acyl (unacylated) ghrelin is the 28-amino-acid ghrelin peptide produced from the preproghrelin precursor (GHRL gene) without the Ser3 octanoyl modification that acylated ghrelin requires to activate the GHSR-1a receptor. https://www.uniprot.org/uniprotkb/Q9UBU3/entry
- [other] Des-acyl ghrelin is the unacylated form of ghrelin, far more abundant in plasma than the acylated hormone; it does not activate GHSR-1a and is proposed to act at a distinct, as-yet-unidentified receptor, as set out in the receptor and metabolic reviews carded on this page (read November 6, 2026).
- [other] US FDA, Drugs@FDA and the drug label endpoint (openFDA), searched November 6, 2026: no approval for des-acyl (unacylated) ghrelin or its analog AZP-531 (livoletide), which was investigational. The native peptide is endogenous; FDA GSRS and ChEMBL hold no approved drug record for it.
Sources & Citations
The six studies carded above were read from their PubMed records on November 6, 2026. Identity comes from UniProt (Q9UBU3, gene GHRL); des-acyl ghrelin's status as the unacylated form of ghrelin, its failure to activate GHSR-1a, its distinct unidentified receptors and its ghrelin-opposing metabolic actions are from the reviews and studies carded here, and the human evidence is the AZP-531 analog trial and metabolic research; the absence of US approval was checked the same day (Drugs@FDA, openFDA, FDA GSRS, ChEMBL). Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.