Ipamorelin

Compliance & Disclaimer

• For Research Use Only
• Not FDA or EMA approved for clinical application
• Evidence is limited to preclinical studies; safety and efficacy in humans remain unestablished.

Ipamorelin is a synthetic pentapeptide classified as a growth hormone secretagogue (GHS) and functions as a highly selective ghrelin receptor (GHS-R1a) agonist. It was first described in the late 1990s as the first selective GHS with minimal off-target endocrine effects compared to earlier peptides like GHRP-6 and GHRP-2. [academic.oup.com], [biolongevitylabs.com]

Mechanistic Insights

• Receptor Selectivity:
  Ipamorelin binds to GHS-R1a, a G-protein-coupled receptor expressed in the hypothalamus and pituitary, initiating phospholipase C activation, IP₃-mediated calcium mobilization, and PKC signaling, which stimulate growth hormone (GH) release from somatotroph cells. [biolongevitylabs.com], [peppydepot.com]

• Minimal Off-Target Hormonal Effects:
  Unlike many GHRPs, Ipamorelin does not significantly increase ACTH, cortisol, prolactin, or aldosterone, even at doses far exceeding those required for GH release. This selectivity allows researchers to study GH-mediated pathways without confounding endocrine responses. [academic.oup.com]

• Pulsatile GH Secretion:
  Research emphasizes that Ipamorelin enhances GH pulse amplitude while preserving physiologic pulsatility, which is critical for downstream IGF-1 signaling, protein synthesis, and tissue remodeling. [nordscipeptides.com]

Research Applications

• Endocrine and Metabolic Studies:
  Ipamorelin is widely used to investigate GH/IGF-1 axis dynamics, energy homeostasis, and metabolic regulation. Preclinical models report effects on bone mineral density, lean body mass, and lipid metabolism, making it relevant for studies on musculoskeletal and metabolic health. [biotechpeptides.com], [peppydepot.com]

• Tissue Repair and Regeneration:
  By amplifying GH pulses, Ipamorelin has been studied in models of connective tissue remodeling, collagen synthesis, and muscle recovery, supporting its role in regenerative biology research. [nordscipeptides.com]

• Gastrointestinal Motility and Appetite Regulation:
  As a ghrelin mimetic, Ipamorelin influences gastric emptying and feeding behavior in animal models, though effects are milder than classic GHRPs. [drugtext.org]

Pharmacokinetics

Ipamorelin exhibits dose-proportional pharmacokinetics, a short half-life (~2 hours), and favorable tolerability in animal and early human studies. Its selectivity profile reduces the risk of cortisol-related side effects observed with other secretagogues. [drugtext.org]

Key Peer-Reviewed References

1. Raun K. et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998;139(5):552–561. DOI:10.1530/eje.0.1390552 [academic.oup.com]
2. Svensson J. et al. The GH secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats. J Endocrinol. 2000;165(3):569–577 [uspeptideco.com]
3. Gobburu J.V. et al. Pharmacokinetic-pharmacodynamic modeling of ipamorelin in human volunteers. Pharm Res. 1999;16(9):1412–1416 [uspeptideco.com]
4. Nordsci Research. Ipamorelin Benefits: Mechanisms, Research Signals, and Comparative Insights. 2025. Link [nordscipeptides.com]
5. Biolongevity Labs. Ipamorelin: The Science Behind the Peptide. 2025. Link [biolongevitylabs.com]