Motilin
Evidence: DGastrointestinal / Gut-Hormone Signaling
Evidence Snapshot
What this grade covers
Applies to native, synthetic-but-sequence-identical human Motilin, administered intravenously to small cohorts of healthy human volunteers in controlled dose-response and mechanistic infusion studies (Kamerling 2002, PMID 11856087; Luiking 2003, PMID 12680909; Luiking 2002, PMID 11975715). This is a genuine, if modest, direct human evidence base -- not absent -- but it consists entirely of small (n<=10), single-session, acute infusion studies measuring GI motility/electromyographic endpoints, never a therapeutic-outcome or larger RCT base. No approved native-Motilin drug exists. Motilin-receptor agonist drugs (erythromycin, azithromycin, camicinal, mitemcinal) have their own, much larger clinical evidence base for indications like gastroparesis, but that evidence belongs to those distinct molecules and is not graded here in any capacity.
Regulatory Context
Native Motilin is an endogenous hormone and is not itself an FDA-approved drug product for any indication. Motilin-receptor agonists (e.g., erythromycin, azithromycin, camicinal, mitemcinal) are chemically distinct, separately regulated compounds; their approval status and clinical indications do not apply to native Motilin.
Research Takeaway
Motilin is an endogenous 22-amino-acid peptide hormone produced by M-cells of the upper small intestine that regulates the interdigestive migrating motor complex (phase III activity) of the stomach and gallbladder.
Evidence boundary: Identity/physiology statement; does not itself establish therapeutic efficacy. Do not use to imply erythromycin or motilide drugs are Motilin.
See all 5 evidence claims →Quick Summary
Motilin is a natural gut hormone that helps trigger the stomach and small intestine's cyclical 'housekeeping' contractions between meals. Small controlled human infusion studies confirm it dose-dependently stimulates gastric antral contractions and gallbladder emptying, with effects that are regionally selective (no confirmed effect on small-intestinal or pyloric motility) and mediated in part through 5HT3 receptor signaling. There is no FDA-approved native-Motilin drug; motilin-receptor-agonist drugs such as erythromycin and newer synthetic motilides are chemically distinct and are not the subject of this page.
Mechanism & Research Overview
Motilin is a natural gut hormone that helps trigger the stomach and small intestine's cyclical 'housekeeping' contractions between meals. Small controlled human infusion studies confirm it dose-dependently stimulates gastric antral contractions and gallbladder emptying, with effects that are regionally selective (no confirmed effect on small-intestinal or pyloric motility) and mediated in part through 5HT3 receptor signaling. There is no FDA-approved native-Motilin drug; motilin-receptor-agonist drugs such as erythromycin and newer synthetic motilides are chemically distinct and are not the subject of this page.
Evidence Claims
Individual scientific statements drawn from the sources cited below, each shown with the specific evidence boundary that statement does not establish.
Supported
Motilin is an endogenous 22-amino-acid peptide hormone produced by M-cells of the upper small intestine that regulates the interdigestive migrating motor complex (phase III activity) of the stomach and gallbladder.
Does not establish
Evidence boundary: Identity/physiology statement; does not itself establish therapeutic efficacy. Do not use to imply erythromycin or motilide drugs are Motilin.
Supported
In controlled human intravenous-infusion studies, native Motilin dose-dependently increases gastric antral contraction frequency and can trigger phase III migrating motor complex activity and gallbladder emptying.
Does not establish
Evidence boundary: Established only via acute IV infusion in small (n<=10), single-session studies in healthy fasted volunteers; a plateau effect was observed between the two higher tested doses; no chronic-use or disease-population data exists for native Motilin itself. Do not generalize to erythromycin/motilide clinical efficacy in gastroparesis or any other indication.
Sources: Dose-Related Effects of Motilin on Proximal Gastrointestinal Motility; Differential Effects of Motilin on Interdigestive Motility of the Human Gastric Antrum, Pylorus, Small Intestine and Gallbladder; Effects of Motilin on Human Interdigestive Gastrointestinal and Gallbladder Motility, and Involvement of 5HT3 Receptors
Supported
Native Motilin's documented human effects are regionally selective: it affects gastric antral and gallbladder motility but has not been shown to affect small-intestinal phase III activity or pyloric motility in controlled human studies.
Does not establish
Evidence boundary: A negative/differential finding within a positive-effect study; absence of effect in one study does not prove impossibility, but no positive human finding for these specific targets was located. Do not state motilin acts uniformly throughout the GI tract.
Supported
Part of native Motilin's effect on gastric phase III activity in humans involves 5HT3 receptor signaling, but its effect on gallbladder emptying appears mechanistically independent of 5HT3 signaling.
Does not establish
Evidence boundary: A single controlled human pharmacological-blockade study; partial (not complete) blockade was observed for the phase III effect. Do not state motilin's gallbladder effect is 5HT3-mediated.
Supported
Motilin-receptor agonist drugs (erythromycin, azithromycin, and synthetic motilides such as camicinal and mitemcinal) are distinct molecules from native Motilin. Their clinical efficacy in conditions such as gastroparesis does not establish native Motilin's own efficacy, safety, or regulatory status, and is not addressed on this page.
Does not establish
Evidence boundary: Firewall/definitional statement. Never cite an erythromycin/motilide gastroparesis trial as native Motilin evidence.
Safety & Evidence Limitations
Considerations reported in the sources cited on this page — not a complete list of every possible risk, and not medical advice.
Safety Consideration
Erythromycin, azithromycin, camicinal, and mitemcinal act on the motilin receptor but are distinct, separately-regulated molecules with their own safety profiles (including, for macrolide antibiotics, cardiac QT-prolongation and antimicrobial-resistance considerations unrelated to native Motilin). None of that safety or efficacy evidence transfers to native Motilin.Safety Consideration
A controlled human study (PMID 12680909) found native Motilin does not affect small-intestinal phase III activity or pyloric IPPWs, despite clear effects on the antrum and gallbladder -- a genuine boundary on where the hormone acts.Safety Consideration
Following a motilin-induced antral phase III, a substantially prolonged refractory period was observed before the next phase III could be triggered (121±13 min vs. 30±13 min under a different preceding condition) -- a desensitization-adjacent finding relevant to any repeated-dosing consideration.Safety Consideration
All three verified controlled human Motilin studies located in this review are acute, single-session, IV infusions in small healthy-volunteer cohorts (n<=10). No chronic administration study or disease-population (e.g., gastroparesis, post-surgical ileus) native-Motilin trial was identified.
Research Areas Being Studied
Research areas discussed on this page reflect the Gastrointestinal / Gut-Hormone Signaling category and the sources cited below.
Findings Reported in Studies
Educational summary only — reported in cited studies, not a claim of proven benefit.
- Differential Effects of Motilin on Interdigestive Motility of the Human Gastric Antrum, Pylorus, Small Intestine and Gallbladder (2003):
- Dose-Related Effects of Motilin on Proximal Gastrointestinal Motility (2002):
- Effects of Motilin on Human Interdigestive Gastrointestinal and Gallbladder Motility, and Involvement of 5HT3 Receptors (2002):
Study Tables by Evidence Type
Human Studies & Clinical Data
| Title | Year | Population / Model | Dose / Duration / Finding | Safety Notes | Source |
|---|---|---|---|---|---|
| Differential Effects of Motilin on Interdigestive Motility of the Human Gastric Antrum, Pylorus, Small Intestine and Gallbladder | 2003 | Motilin initiates antral phase III activity and gallbladder emptying and induces a prolonged refractory period for subsequent antral phase III (121±13 min vs. 30±13 min when a duodenal phase III preceded); small-intestinal phase IIIs and pyloric IPPWs are NOT affected by motilin. | Explicit negative/regional-selectivity finding -- motilin does not act uniformly throughout the GI tract. | ||
| Dose-Related Effects of Motilin on Proximal Gastrointestinal Motility | 2002 | 10 fasted healthy volunteers | IV synthetic human motilin (0.5/1/2/4 pmol.min/kg vs. placebo) produced a dose-related increase in antral contraction frequency, significant at 2 and 4 pmol.min/kg (a ceiling/plateau effect between the two higher doses); no changes in gastric myoelectrical activity were observed and gallbladder-volume changes were not statistically significant at these doses. | Small (n=10), single-session, acute study in fasted healthy volunteers. | |
| Effects of Motilin on Human Interdigestive Gastrointestinal and Gallbladder Motility, and Involvement of 5HT3 Receptors | 2002 | Motilin shortened the interval to phase III from 95.0 to 28.7 minutes vs. saline and decreased gallbladder volume within 10 minutes of infusion; the 5HT3 antagonist ondansetron partially blocked the phase III-shortening effect (interval increased to 39.3 min) but had no effect on gallbladder emptying. | Genuine mechanistic dissociation -- motilin's antral/phase-III effect and gallbladder effect are not fully mediated by the same pathway. |
Animal / Cell / Preclinical Data
No Animal / Cell / Preclinical Data Listed Yet
This section will be updated as sources are added.
Regulatory Documents & Official Trial Registries
No Regulatory Documents & Official Trial Registries Listed Yet
This section will be updated as sources are added.
Anecdotal Reported Patterns — Not Medical Advice
Anecdotal Reported Patterns — Not Medical Advice
Reported dosing patterns are included for educational context only. They are self-reported, unverified, not medical advice, and not instructions for human use. Community-submitted patterns are not yet available in this Phase 1 prototype; this section is a placeholder reserved for moderated, aggregated community data.
Lab Markers to Discuss With a Clinician
Educational topics only — not self-monitoring instructions.
FAQ
Disclaimer
Educational information only. This page summarizes published research on endogenous Motilin and does not constitute medical advice, a treatment recommendation, or dosing guidance for any motilin-related substance or motilin-receptor-agonist drug.
Educational use only. This content is provided for informational and research-summary purposes only. It is not medical advice, not a treatment recommendation, not a dosing guide, and not a substitute for care from a licensed medical professional. Nothing here is intended to diagnose, treat, cure, prevent, or mitigate disease. Reported dosing patterns, when shown elsewhere on the site, must be labeled either as Study / Trial Dosing or Anecdotal Reported Patterns — Not Medical Advice. Community reports are self-reported, unverified, and not scientific proof.
Community-reported experiences, once enabled, must be displayed only as moderated, anonymized, or aggregated data. They are anecdotal, self-reported, unverified, and should never be presented as proof of safety, efficacy, or expected results.
Content status: Published. Last updated 2026-08-26.
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