Evidence Tier: Phase 1-2 Clinical Data — Ipamorelin is a selective growth hormone secretagogue receptor (GHS-R) agonist. It stimulates GH release without significantly affecting cortisol, prolactin, or ACTH levels.
Overview
Ipamorelin is a pentapeptide (Aib-His-D-2Nal-D-Phe-Lys-NH2) that acts as a selective agonist of the ghrelin/growth hormone secretagogue receptor (GHS-R1a). It was developed by Novo Nordisk in the late 1990s and is notable for its high selectivity — it stimulates growth hormone release without significantly elevating cortisol, ACTH, or prolactin, distinguishing it from earlier GH secretagogues like GHRP-6.
Mechanism of Action
- Selective binding to GHS-R1a in the anterior pituitary
- Dose-dependent GH release that follows natural pulsatile patterns
- Does not significantly affect cortisol, prolactin, or ACTH at therapeutic doses
- Synergistic effect when combined with GHRH analogs (e.g., CJC-1295)
Clinical Research
Phase 1-2 studies demonstrated dose-dependent increases in GH levels. A study of postoperative ileus recovery showed ipamorelin accelerated GI recovery time. However, development was discontinued by Novo Nordisk, and no Phase 3 trials were completed.
References
- Raun K, et al. "Ipamorelin, the first selective growth hormone secretagogue." Eur J Endocrinol. 1998;139(5):552-561.
- Beck DE, et al. "Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus." Int J Colorectal Dis. 2014;29(12):1527-1534.
Research Disclaimer
This article is compiled from peer-reviewed research and publicly available scientific literature. It is intended for educational and informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before making health-related decisions.