Evidence review: Open Peptide Project (verified against primary PubMed, ClinicalTrials.gov & FDA records) · Last checked 2026-10-27. ← Back to Evidence Library

Relamorelin (RM-131): what the evidence says

Name: Relamorelin (RM-131)
Published: 2026-10-27

At a glance

What it is: a synthetic 5-amino-acid peptide that activates the ghrelin receptor, developed to speed stomach emptying. ^R1 Never approved; its phase 3 program was stopped. ^{R2, R3}

What the evidence says: Human two phase 2 trials in diabetic gastroparesis improved symptoms and stomach emptying vs placebo, ^{R1, R4} but four phase 3 trials were stopped early, and the posted results show symptom scores improving about as much on placebo. ^{R2, R3, R5, R6}

Biggest risks: worse blood-sugar control (14.5% in the phase 2b), with HbA1c rising with dose. ^{R4, R7}

Rating


Human Human evidence	Limited: two positive phase 2 RCTs (n = 204 and 393) vs phase 3 results showing no clear difference ^{R1, R4, R2}
Animal Animal / lab evidence	Not reviewed
Regulatory	Never approved; development stopped ^R2 · not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page ^{R8, R9, R10} · not named by WADA, but as a ghrelin-receptor agonist it falls in the GHS-mimetic class under S2.2.4 ^R11
Established human dose	No (trial amounts only; see Study details)

Evidence verdict: Diabetic gastroparesis: Limited (positive phase 2 RCTs; four phase 3 trials stopped early, posted results show no clear difference from placebo) · Chronic constipation: Very limited (small short studies) · Muscle or appetite gain: No human data

This page reports what studies used. It is not dosing advice.

Legend: HUMAN data · ANIMAL / LAB data · UNKNOWN · UNVERIFIED: not yet confirmed against a primary source

About the evidence: the phase 3 trials posted only raw group results with no formal analysis, and they ended early. That limits firm conclusions, but they did not confirm the phase 2 benefit.

What is it?

Related pages: anamorelin, macimorelin.

Does it work?

Human Phase 2 (n = 204): the twice-daily dose reduced vomiting by about 60% and sped stomach emptying vs placebo, but did not improve pain or fullness overall. ^R1
Human Phase 2b (12 weeks, n = 393): all three doses reduced core gastroparesis symptoms and sped stomach emptying by about 12% vs placebo. ^{R4, R12}
Human Phase 3 (four trials, 311 to 467 enrolled, all terminated): at 12 weeks, symptom scores fell by similar amounts on relamorelin and placebo (for example −9.3 vs −10.0 and −10.2 vs −9.3). No formal statistics were posted. ^{R2, R3, R5, R6}
Human Chronic constipation: one dose increased colon contractions in a small, short study. ^R13
Unknown Parkinson's constipation (MOVE-PD): only 18 of a planned 56 completed, so no conclusion. ^R14

Is it safe?

Human Worsened blood-sugar control in 14.5% in the phase 2b; HbA1c rose with dose in pooled data. ^{R4, R7}
Human One death (urosepsis) in phase 2b was judged unrelated. ^R7
As a ghrelin-receptor agonist it may raise growth hormone; UNVERIFIED long-term effects not studied.

Pipeline status (investigational)

Sponsor: Allergan. ^R12 UNVERIFIED original developer (reported as Rhythm) and current rights holder.
Status: all four phase 3 trials terminated; results posted. ^{R2, R3, R5, R6}
Expected readouts: none.

Gray-market vials: extra risks

A gray-market vial has no quality control and no guarantee of identity, strength or sterility. We test retail vials blind under the Open Peptide Standard; see /tests/. A passing test covers one batch on one date and does not mean the compound is safe.

Is it legal?

US: not FDA-approved; no Drugs@FDA application found (openFDA searched Oct 27, 2026).
Compounding: not on FDA's 503A or 503B bulk-substance category lists and not on FDA's compounding safety-risk page. ^{R8, R9, R10}
Sport: not named, but WADA prohibits growth hormone secretagogues and their mimetics at all times under S2.2.4, and relamorelin acts on the same receptor. ^R11

Study details

These are amounts researchers used, not recommendations.

Study	People / model	Route	Amount used	Follow-up	Reported	Citation
Lembo 2016 (phase 2)	204 adults with diabetic gastroparesis	Subcutaneous	10 µg once or twice daily	Per protocol	Twice-daily dose: less vomiting, faster emptying	PMID 27055601
Camilleri 2017 (phase 2b)	393 adults with diabetic gastroparesis	Subcutaneous	10, 30 or 100 µg twice daily	12 weeks	Fewer symptoms vs placebo	PMID 28760384
Phase 3 (NCT03285308, NCT03426345)	336 and 311 enrolled	Subcutaneous	Per protocol	12 weeks	Symptom change similar to placebo	^{R2, R3}
Acosta 2016 (constipation)	Adults with chronic constipation	Subcutaneous	100 µg single dose	Single dose	More colon contractions	PMID 26467700

Full reference list (PubMed, CT.gov, FDA and WADA checked Oct 27, 2026)

^R1 Lembo A, et al. Gastroenterology. 2016. PMID 27055601
^R2 ClinicalTrials.gov NCT03285308, phase 3 in diabetic gastroparesis, terminated, 336 enrolled, results posted (CT.gov API v2, checked Oct 27, 2026). https://clinicaltrials.gov/study/NCT03285308
^R3 ClinicalTrials.gov NCT03426345, phase 3 in diabetic gastroparesis, terminated, 311 enrolled, results posted (CT.gov API v2, checked Oct 27, 2026). https://clinicaltrials.gov/study/NCT03426345
^R4 Camilleri M, et al. Gastroenterology. 2017. PMID 28760384
^R5 ClinicalTrials.gov NCT03420781, phase 3 extension in diabetic gastroparesis, terminated, 467 enrolled, results posted (CT.gov API v2, checked Oct 27, 2026). https://clinicaltrials.gov/study/NCT03420781
^R6 ClinicalTrials.gov NCT03383146, phase 3 in diabetic gastroparesis, terminated, 450 enrolled, results posted (CT.gov API v2, checked Oct 27, 2026). https://clinicaltrials.gov/study/NCT03383146
^R7 Camilleri M, et al. Aliment Pharmacol Ther. 2020. PMID 32301137
^R8 FDA, 503A bulk drug substances categories list (updated May 14, 2026). https://www.fda.gov/media/94155/download
^R9 FDA, 503B bulk drug substances categories list (updated Mar 21, 2025). https://www.fda.gov/media/94164/download
^R10 FDA, Certain bulk drug substances for use in compounding that may present significant safety risks (content current Apr 22, 2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
^R11 WADA. The 2026 Prohibited List, S2.2.4, Growth hormone releasing factors, including growth hormone secretagogues (GHS) and their mimetics; relamorelin not named. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
^R12 ClinicalTrials.gov NCT02357420, phase 2b in diabetic gastroparesis, Allergan, completed, 393 enrolled (CT.gov API v2, checked Oct 27, 2026). https://clinicaltrials.gov/study/NCT02357420
^R13 Acosta A, et al. Dig Dis Sci. 2016. PMID 26467700
^R14 Parkinson Study Group. Electronic address: [email protected]. Parkinsonism Relat Disord. 2017. PMID 28237854

Disclaimer

This page is for education and harm reduction, not medical advice or a recommendation to use Relamorelin (RM-131). This drug was never approved and its development has stopped. Products sold online under this name are unregulated. Report problems to FDA MedWatch (https://www.fda.gov/safety/medwatch).