Ipamorelin
Research OnlyA growth hormone secretagogue that stimulates GH release without significant effects on cortisol or prolactin. Developed by Novo Nordisk (Denmark); limited clinical development despite promising early data.
NNC 26-0161 · NNC-26-0161
4 human studies
- Preclinical
- 50%
- Clinical
- 22%
Based on 18 cited sources
clinically demonstrated · low confidence
Demonstrated effect magnitude — not a recommendation or safety claim.
Research Depth 62: highest human tier is a single adequately-powered Phase 2 RCT (Beck 2014 postoperative ileus, N=114, PMID 25331030) plus a clinical PK/PD dose-escalation trial (Gobburu 1999, n=40, PMID 10496658) (1A 28); Beck is multicenter double-blind placebo-controlled, low-ish RoB but no systematic review (1B 14); total human N ~157 in the 50-300 band (1C 6); directness partial - the powered RCT measured gut motility while the PK trial measured the GH surrogate, not the community anti-aging/body-comp uses (1D 7); substantial multi-study preclinical program across rat/swine/dog (Raun 1998, Svensson 2000 bone, Johansen 1999, NN703 derivative) (1E 7). Mechanism 95: GHS-R1a target confirmed by binding plus GHRP/GHRH-antagonist abolition of effect (Raun 1998 PMID 9849822) (2A 40); full Gq/11 -> PLC -> IP3/DAG -> Ca2+ -> GH -> IGF-1 pathway characterized (2B 27); consistent monotonic dose-response across rat pituitary cells, in-vivo rats/swine and human PK/PD (2C 18); confirmed in mammalian in vivo and humans (2D 10). Plausibility 77: mechanism->surrogate (GH release) directly proven in humans, surrogate-> downstream benefit inferred and the one powered clinical efficacy trial (POI) failed (3A 26); fully coherent with GH/ghrelin physiology (3B 24); multiple same-class GHRPs (GHRP-6/GHRP-2/MK-677/hexarelin) reliably release GH (3C 18); core claim tightly scoped but dossier extends to sleep/recovery/anti-aging (3D 9). Global Coverage 53: replicated across Novo Nordisk (Denmark), Sahlgrenska (Sweden) and a US multicenter POI RCT (4A 22); ~3 countries / several institutions (4B 13); ~18-study modest literature (4C 13); ClinicalTrials.gov registration NCT00672074 but never approved (4D 5). Community Experience 75: broad, persistent multi-community discussion as a popular mild GHRP (5A 24), >7 years of sustained use (5B 24), broadly consistent "subtle/slow/cleaner than GHRP-6" themes (5C 15), no recurring serious adverse signal beyond minor flushing (5D 12). Effectiveness basis clinical but low (18): the only powered human efficacy trial (POI) showed no benefit vs placebo (25.3 vs 32.6 h, p=0.15); the demonstrated human effect is GH elevation, a surrogate biomarker, so E3 outcome relevance and E4 vs-best-option score low. Confidence low - a single failed clinical efficacy RCT with surrogate-only positive evidence.
The proposed mechanisms of ipamorelin are based on clinical and preclinical studies. Human data exists but is limited to short-term Phase 1/2 trials.
How It Works (Simplified)
Ipamorelin acts as a selective growth hormone secretagogue through the ghrelin receptor:
Binds to the ghrelin receptor (GHS-R1a) on pituitary somatotrophs, triggering growth hormone release through Gq/11 protein activation.
Stimulates growth hormone secretion without elevating cortisol or prolactin levels, unlike older GH secretagogues (GHRP-6, GHRP-2).
Mimics natural GH release pattern with discrete pulses rather than constant elevation, preserving physiological hormone rhythms.
High receptor selectivity results in minimal side effects compared to less selective GH secretagogues, with no significant appetite stimulation.
Key Research: Raun K et al. (Novo Nordisk, Denmark, 1998) identified ipamorelin as first selective GH secretagogue. PMID:9849822
Important Limitations
- Not approved by FDA, EMA, or any regulatory agency
- Phase 2 clinical trial for post-operative ileus failed to meet primary endpoint
- Long-term safety data not available
- Prohibited in athletic competition by WADA
- Translation from preclinical to human outcomes is not fully established
Reported positives
- Improved sleep quality and deeper sleep reported
- Subtle body composition improvements over time
- Fewer side effects compared to other GH secretagogues
- Improved recovery from exercise reported
Reported negatives
- Effects subtle and slow to manifest
- Injection timing and fasting requirements inconvenient
- Head rush or flushing shortly after injection
- Results plateau after extended use
“Popular GH secretagogue considered milder than GHRP options. Often combined with CJC-1295.”
Self-reported, unverified accounts — not clinical evidence and no substitute for the cited research. Anecdotes are prone to selection bias and placebo effects.
| NCT ID | Title | Peptide | Phase | Status | Completion |
|---|---|---|---|---|---|
| NCT00672074 | Ipamorelin for Postoperative Ileus Ileus | Ipamorelin | Phase 2 | Completed | Dec 2009 |
| NCT01280344 | Dose-Finding Study of Ipamorelin for Post-Surgical GI Recovery Gastrointestinal Dysmotility | Ipamorelin | Phase 2 | Completed | Jun 2013 |
Dose-Finding Study of Ipamorelin for Post-Surgical GI Recovery
Based on Phase 1 data: GH release begins within 15-30 minutes of injection. Peak GH levels occur approximately 30-60 minutes post-injection. Effects are acute and pulsatile.
PMID:9849822With daily or twice-daily dosing, GH pulsatility patterns established. Early studies showed dose-dependent GH release without significant cortisol or prolactin elevation. No desensitization observed.
PMID:9849822Sustained GH/IGF-1 elevations with continued use. Gastrointestinal motility effects noted in post-operative trials. Body composition changes may begin to become apparent.
PMID:25331030Limited long-term data. Phase 2 POI trials used short-term administration. Extended use outcomes not well-characterized in clinical trials. No approved indications exist.
Research-based observations
This timeline reflects observations from published clinical and preclinical studies. Individual responses may vary significantly. This is not a guarantee of effects or a dosing schedule. Consult qualified healthcare providers for personalized guidance.
Good Signs (6 indicators)
Warning Signs (5 indicators)
Bad Signs (7 indicators)
For Research Evaluation Only
These quality indicators are general guidelines based on typical peptide characteristics. Professional laboratory testing (HPLC, mass spectrometry) provides definitive quality verification. This checklist is for initial visual evaluation only.
CJC-1295
SynergisticFrequently combined in research. Ipamorelin (ghrelin receptor) and CJC-1295 (GHRH receptor) act through complementary pathways, potentially producing additive GH release effects.
Sermorelin
SynergisticGHRH + GHRP synergy demonstrated in human studies. Sermorelin amplifies the GH pulse while ipamorelin initiates release. Combined effect may exceed either alone.
Tesamorelin
SynergisticTesamorelin (GHRH analog) and ipamorelin (GHRP) act through complementary pathways. Established GHRH+GHRP synergy in GH release.
GHRP-6
CompatibleBoth act on ghrelin receptor with different selectivity profiles. Ipamorelin is more selective with less cortisol/prolactin effects. No clear benefit to combining same-mechanism agents.
GHRP-2
CompatibleSame receptor target (GHS-R1a). GHRP-2 is more potent but less selective. No established rationale for combination.
MK-677
CompatibleBoth stimulate GH via ghrelin pathway. MK-677 is oral with longer duration. May be redundant to combine, though mechanisms slightly differ.
Semaglutide
CautionGH secretagogues may affect glucose metabolism. Monitor blood glucose if using with GLP-1 agonists in diabetic patients.
Research Note: Interaction data is based on published literature, mechanistic understanding, and theoretical considerations. Most peptide combinations lack direct clinical study. This information is for educational purposes only and does not constitute medical advice. Always consult qualified healthcare providers.
Key Studies Cited
Full reference list available on request. All citations link to PubMed for verification.
This dossier synthesizes available evidence from peer-reviewed literature, regulatory documents, and clinical trial registries. Evidence strength ratings follow a modified GRADE approach.
For complete methodology details, see our Methodology page.
Important Disclaimer
This dossier is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before making health decisions.
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