Relamorelin
A synthetic pentapeptide that mimics ghrelin to speed the stomach, tested in diabetic gastroparesis until its phase 3 programme was stopped
Relamorelin activates the ghrelin receptor and speeds gastric emptying. Two phase 2 trials in diabetic gastroparesis were positive on emptying and symptoms, but all five phase 3 trials were terminated in 2020 for what the sponsor called a business decision, and it is not approved anywhere.
What is it?
Ghrelin is the hormone that rises before meals; besides stimulating appetite, it speeds the stomach and gut. Relamorelin is a synthetic pentapeptide built to activate the same receptor, GHS-R1a, and its development targeted diabetic gastroparesis, a condition in which the stomach empties too slowly and causes nausea, vomiting, fullness and pain. Ghrelin itself lasts too briefly to be practical, which is the reason longer-acting mimetics were made.
The phase 2 trials were encouraging. In 204 patients, 10 µg twice daily accelerated gastric emptying and cut vomiting by about 60% against placebo, without improving pain or fullness overall. In a 12-week phase 2b trial in 393 patients, all four core symptoms improved at every dose and emptying accelerated by 12%, though vomiting was not significantly better than placebo. A pooled analysis of five trials (1,033 participants) found emptying about 11 minutes faster.
Blood sugar was the recurring concern. In phase 2b, glycaemic control worsened in 14.5% of patients on relamorelin, in a dose-related way, and a safety review of both trials confirmed dose-related rises in HbA1c and fasting glucose, with more discontinuations for adverse events than on placebo.
It was also tried elsewhere. In 48 women with chronic constipation, 100 µg daily accelerated colonic transit and increased bowel movements over two weeks; in 22 women with anorexia nervosa, four weeks shortened gastric emptying with a trend toward weight gain. A pressure study in chronic constipation showed it triggered more propagated colonic contractions, the movements that push stool forward, but a trial in Parkinson's disease constipation could not recruit enough patients to test it.
The blood-sugar effect that troubled the gastroparesis trials has found a new use in the laboratory. In mice carrying islets that oversecrete insulin, modelling congenital hyperinsulinism, relamorelin raised glucose, and with octreotide it reversed hypoglycaemia. Reviews written in 2017 anticipated phase 3 and described it as free of cardiac or neurological side effects.
ClinicalTrials.gov lists all five phase 3 trials in diabetic gastroparesis as terminated between July and November 2020, each because the programme was ended on a business decision. No phase 3 results are on PubMed, and relamorelin is not approved anywhere.
Mechanism of Action
Relamorelin is a synthetic pentapeptide agonist of the ghrelin receptor (GHS-R1a), developed to speed the stomach and gut.
Gastric emptying
It accelerated gastric emptying in diabetic gastroparesis, about 11 minutes faster in pooled trials.
Colonic propulsion
It induced propagated colonic contractions and faster colonic transit in chronic constipation.
Blood glucose
Ghrelin receptor activation raises glucose: HbA1c rose in trials, and in mice it countered hyperinsulinism.
Published Research
The studies behind relamorelin, read from their PubMed abstracts: the gastroparesis trials, pooled safety and efficacy, and its use in constipation, anorexia nervosa and healthy volunteers.
Phase 2b in diabetic gastroparesis
In 393 patients over 12 weeks, all four core symptoms improved at 10, 30 and 100 µg against placebo and emptying accelerated by 12%; vomiting fell 75% from baseline but not significantly versus placebo, and glycaemic control worsened in 14.5%.
Phase 2a: vomiting and emptying
In 204 patients, 10 µg twice daily accelerated gastric emptying and reduced vomiting frequency by about 60% against placebo, without improving pain or satiety overall.
Safety across both phase 2 trials
Serious adverse events matched placebo; discontinuations were higher on relamorelin and HbA1c rose with dose.
Chronic constipation in 48 women
Over 14 days, 100 µg daily accelerated colonic transit and increased spontaneous bowel movements against placebo.
Healthy volunteers: antral motility
In 16 volunteers, 30 µg increased distal antral contractions after a meal without changing gastric volumes or satiation.
Colonic contractions in constipation
In patients with chronic constipation, relamorelin 100 µg induced more propagated colonic contractions before and after a meal than placebo, without changing colonic tone or compliance.
MOVE-PD: constipation in Parkinson's
A placebo-controlled trial in Parkinson's disease constipation enrolled only 18 of the intended 56 patients, partly because many had frequent incomplete movements rather than infrequent stools, so no benefit could be shown.
Why a ghrelin mimetic
A review explains that ghrelin's short half-life limits its clinical use, which is why longer-acting receptor agonists such as relamorelin were developed for gastroparesis, functional dyspepsia and reflux that resists proton pump inhibitors.
Meta-analysis of five randomised trials
Across 1,033 participants, relamorelin shortened gastric emptying by a mean 11.4 minutes against placebo (8.4 minutes in diabetic gastroparesis), with headache, dizziness and gastrointestinal effects among adverse events.
Where it stood in 2017
A 2017 review summarised phase 2 results, noted that phase 2b did not reduce vomiting but improved four other symptoms and gastric emptying, reported no cardiac or neurological adverse effects, and anticipated phase 3.
Constipation and the ghrelin receptor
A review describes how centrally penetrant ghrelin receptor agonists stimulate defecation through vagal and pelvic nerves and summarises relamorelin's lower-gut results.
A gastrocolokinetic ghrelin analogue
An early review collected phase 2a results showing faster gastric emptying in type 1 and type 2 diabetes and faster colonic transit in chronic constipation.
Congenital hyperinsulinism in mice
In mice engrafted with stem-cell islets from congenital hyperinsulinism, relamorelin raised fasting glucose, and with octreotide it synergistically reversed hypoglycaemia while lowering excess insulin.
Dosing Data
Never approved. Trials gave it by subcutaneous injection, from 10 µg twice daily in gastroparesis to 100 µg daily in constipation.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or 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.
Side Effects & Contraindications
Reported Side Effects
From the trials above.
Contraindications & Cautions
An investigational drug with no label.
Legal Status
Not approved; development stopped in phase 3.
Frequently Asked Questions
?What is relamorelin?
A synthetic pentapeptide that activates the ghrelin receptor to speed the stomach and gut, developed for diabetic gastroparesis.
?Did it work?
In phase 2 it sped gastric emptying and, in the larger trial, improved core gastroparesis symptoms against placebo, though vomiting was not significantly better than placebo in that trial.
?Why was it never approved?
Its five phase 3 trials were terminated in 2020; ClinicalTrials.gov gives the reason as a business decision. No phase 3 results are published.
?Does it affect blood sugar?
Yes. In the phase 2b trial, glycaemic control worsened in 14.5% of patients, in a dose-related way.
?Did relamorelin help constipation?
In 48 women with chronic constipation, 100 µg daily accelerated colonic transit and increased bowel movements over two weeks, and it triggered more propagated colonic contractions. A trial in Parkinson's disease constipation could not recruit enough patients.
References
- [pubmed] Camilleri M, et al. "Efficacy and Safety of Relamorelin in Diabetics With Symptoms of Gastroparesis: A Randomized, Placebo-Controlled Study." Gastroenterology, 2017;153(5):1240-1250.e2. PMID: 28760384.
- [pubmed] Lembo A, et al. "Relamorelin Reduces Vomiting Frequency and Severity and Accelerates Gastric Emptying in Adults With Diabetic Gastroparesis." Gastroenterology, 2016;151(1):87-96.e6. PMID: 27055601.
- [pubmed] Camilleri M, et al. "Overall safety of relamorelin in adults with diabetic gastroparesis: Analysis of phase 2a and 2b trial data." Aliment Pharmacol Ther, 2020;51(11):1139-1148. PMID: 32301137.
- [pubmed] Acosta A, et al. "Relamorelin Relieves Constipation and Accelerates Colonic Transit in a Phase 2, Placebo-Controlled, Randomized Trial." Clin Gastroenterol Hepatol, 2015;13(13):2312-9.e1. PMID: 26001337.
- [pubmed] Nelson AD, et al. "Effects of ghrelin receptor agonist, relamorelin, on gastric motor functions and satiation in healthy volunteers." Neurogastroenterol Motil, 2016;28(11):1705-1713. PMID: 27283792.
- [pubmed] Patel A, et al. "Relamorelin in Gastroparesis and Diabetic Gastroparesis: A Meta-Analysis on Its Efficacy and Safety." Cureus, 2023;15(11):e48303. PMID: 38058346.
- [pubmed] Fazeli PK, et al. "Treatment With a Ghrelin Agonist in Outpatient Women With Anorexia Nervosa: A Randomized Clinical Trial." J Clin Psychiatry, 2018;79(1). PMID: 29325236.
- [clinicaltrials] ClinicalTrials.gov: relamorelin phase 3 trials NCT03285308, NCT03420781, NCT03426345, NCT03383146 and NCT03786380, all terminated in 2020, reason given: 'The Relamorelin program is being terminated solely based on a business decision.' Read October 6, 2026.
- [pubmed] Acosta A, et al. "Short-Term Effects of Relamorelin on Descending Colon Motility in Chronic Constipation: A Randomized, Controlled Trial." Dig Dis Sci, 2016;61(3):852-60. PMID: 26467700.
- [pubmed] "A randomized trial of relamorelin for constipation in Parkinson's disease (MOVE-PD): Trial results and lessons learned." Parkinsonism Relat Disord, 2017;37:101-105. PMID: 28237854.
- [pubmed] Chedid V, et al. "Relamorelin for the treatment of gastrointestinal motility disorders." Expert Opin Investig Drugs, 2017;26(10):1189-1197. PMID: 28847163.
- [pubmed] Mosińska P, et al. "Future Treatment of Constipation-associated Disorders: Role of Relamorelin and Other Ghrelin Receptor Agonists." J Neurogastroenterol Motil, 2017;23(2):171-179. PMID: 28238253.
- [pubmed] Camilleri M, et al. "Emerging treatments in Neurogastroenterology: relamorelin: a novel gastrocolokinetic synthetic ghrelin agonist." Neurogastroenterol Motil, 2015;27(3):324-32. PMID: 25545036.
- [pubmed] Lithovius V, et al. "Ghrelin and relamorelin counteract hypoglycemia in mice engrafted with congenital hyperinsulinism stem cell-derived islets." Stem Cells Transl Med, 2026;15(8). PMID: 42556326.
- [pubmed] Zatorski H, et al. "Relamorelin and other ghrelin receptor agonists - future options for gastroparesis, functional dyspepsia and proton pump inhibitors-resistant non-erosive reflux disease." J Physiol Pharmacol, 2017;68(6):797-805. PMID: 29550791.
Sources & Citations
Studies were read from their PubMed abstracts; phase 3 status from ClinicalTrials.gov (read October 6, 2026). Read October 7, 2026.
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