Ipamorelin
Research OnlyAlso known as: NNC 26-0161, NNC-26-0161
A 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.
Research Statistics
GHRP with moderate research body but limited human trial count (4 human studies); GHS-R1a mechanism is shared with hexarelin and ghrelin, providing mechanistic plausibility.
Research Dossier
Overview
What is Ipamorelin and what does the research say?
Mechanism of Action
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.
Scientific Pathways
GHS-R1a/Gq/11 Pathway (GH Release)
Ipamorelin → GHS-R1a (ghrelin receptor) → Gq/11 activation → PLC → IP3/DAG
↓
Ca²⁺ release → GH secretionIGF-1 Cascade (Downstream Effects)
GH release → Hepatic IGF-1 production → Systemic anabolic effectsKey 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
Evidence-Chained Benefits
Evidence-Chained Benefits
Research findings linked to mechanisms and clinical outcomes
What to Expect
Timeline based on observations from published studies. Individual responses may vary.
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.
With 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.
Sustained GH/IGF-1 elevations with continued use. Gastrointestinal motility effects noted in post-operative trials. Body composition changes may begin to become apparent.
Limited 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.
Quality Checklist
Visual indicators to help evaluate Ipamorelin product quality
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.
Peptide Interactions
Known and theoretical interactions when combining Ipamorelin with other peptides. Based on published research and mechanistic considerations.
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.
References
Key Studies Cited
Full reference list available on request. All citations link to PubMed for verification.
Methodology Note
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.
Get Research Alerts
New dossiers and major study summaries delivered to your inbox. Evidence-graded, citation-backed research you can trust.
No spam. Unsubscribe anytime.
Compare Ipamorelin
Ipamorelin Calculators
Related Peptides
Follistatin
FST, FS-344, FS-315 +1 more
An endogenous glycoprotein that inhibits myostatin and activin signaling, potentially allowing muscle growth beyond genetic limits. Gene therapy trials for muscular dystrophy show promise, but injectable peptide forms remain unapproved and understudied in humans.
GHRP-2
Growth Hormone Releasing Peptide-2, Pralmorelin, KP-102
A synthetic hexapeptide GH secretagogue with the strongest GH-releasing potency in its class. More potent than GHRP-6 with different side effect profile: less appetite stimulation but greater cortisol and prolactin elevation. Approved in Japan as Pralmorelin for GH deficiency diagnosis. Extensively studied in human pharmacology with robust clinical data.
Human Chorionic Gonadotropin (hCG)
hCG, Choriogonadotropin, Pregnyl +5 more
A glycoprotein hormone FDA-approved for ovulation induction, cryptorchidism, and hypogonadotropic hypogonadism. Functions as an LH receptor agonist with over 50 years of clinical use in reproductive medicine. Gold standard trigger for assisted reproductive technology.
Hexarelin
Examorelin, HEX, Growth Hormone Releasing Hexapeptide +2 more
The most potent synthetic GHRP (Growth Hormone Releasing Peptide), a hexapeptide that strongly stimulates GH release via the ghrelin receptor. Notable for cardioprotective effects independent of GH release. Development discontinued due to rapid desensitization with repeated dosing. Italian research leads global investigation.
HMG
Human Menopausal Gonadotropin, Menotropins, hMG +4 more
A urinary-derived glycoprotein hormone preparation containing both FSH and LH in approximately 1:1 ratio, FDA-approved for female infertility (ovulation induction, ART) and male hypogonadotropic hypogonadism. First used clinically in 1961 by Bruno Lunenfeld, HMG enabled the birth of the first American IVF baby in 1981 and remains a cornerstone of fertility medicine with over 60 years of clinical experience. Highly purified preparations (HP-hMG) demonstrate comparable or slightly superior live birth rates compared to recombinant FSH in IVF.
IGF-1 LR3
Long R3 IGF-1, LR3-IGF-1, Insulin-like Growth Factor 1 Long R3
A modified form of IGF-1 with an extended half-life due to reduced binding protein affinity. Used primarily in research for muscle growth and metabolic effects. Not approved for human use; significant safety concerns exist.
Related Content
GHRP-6
Hormonal · moderate evidence
CJC-1295
Hormonal · moderate evidence
Sermorelin
Hormonal · moderate evidence
What is Ipamorelin?
An introduction to ipamorelin, a selective growth hormone se...
CJC-1295 vs Ipamorelin
View side-by-side analysis
GHRP-2 vs Ipamorelin
View side-by-side analysis