What Is Ipamorelin?

Ipamorelin is a synthetic pentapeptide that acts as a selective growth hormone secretagogue (GHS). Developed by Novo Nordisk, it's notable for being one of the most selective GH-releasing peptides, stimulating GH release without significantly affecting cortisol, prolactin, or other hormones.

Sequence: Aib-His-D-2-Nal-D-Phe-Lys-NH2 Molecular Formula: C38H49N9O5 Molecular Weight: 711.85 g/mol Type: Growth Hormone Secretagogue Receptor: Ghrelin receptor (GHS-R1a)

Ipamorelin mimics ghrelin, the body's natural hunger hormone, by binding to the ghrelin receptor in the pituitary gland. However, its selectivity for GH release distinguishes it from other peptides in its class.

Key Characteristics

  • Selectivity: Highly selective for GH release
  • No Cortisol Spike: Doesn't significantly increase cortisol
  • No Prolactin Effect: Minimal impact on prolactin
  • No Appetite Increase: Less hunger stimulation than GHRP-6

Mechanism of Action

Ghrelin Receptor Activation

Ipamorelin works through the ghrelin receptor pathway:

  • Binds to GHS-R1a (ghrelin receptor) on pituitary somatotrophs
  • Triggers release of stored growth hormone
  • Works synergistically with GHRH (different pathway)
  • Maintains natural pulsatile GH secretion pattern

Why "Selective"?

Compared to other GHRPs (like GHRP-6 or GHRP-2):

  • Produces cleaner GH release without cortisol elevation
  • Doesn't significantly raise ACTH or prolactin
  • Minimal ghrelin-like hunger stimulation
  • More targeted physiological response

Dose-Response Relationship

Research has characterized ipamorelin's dose-response:

  • Dose-dependent GH release up to a saturation point
  • No additional benefit from very high doses
  • Typical research doses: 100-300 mcg
  • Effect amplified when combined with GHRH analogs

Research Findings

Growth Hormone Release

  • Robust GH release comparable to GHRP-6
  • Peak GH levels within 30-45 minutes of administration
  • Duration of effect: approximately 3 hours
  • Maintains efficacy with repeated administration

Body Composition Studies

  • Potential increases in lean body mass in animal studies
  • Fat mass reduction observed in some models
  • Bone density improvements suggested
  • Limited human clinical data available

Post-Operative Recovery

Ipamorelin has been studied for post-surgical recovery:

  • Clinical trials in post-operative ileus (bowel function)
  • Investigated for accelerating GI recovery after surgery
  • Mixed results in Phase III trials
  • Development discontinued for this indication

Combined with CJC-1295

A popular research combination:

  • CJC-1295 (GHRH analog) + Ipamorelin (GHRP)
  • Different mechanisms create synergistic effect
  • Greater GH release than either peptide alone
  • Commonly studied together in research settings

Comparison with Other GH Secretagogues

Peptide GH Release Cortisol Prolactin Hunger
Ipamorelin +++ Minimal Minimal Minimal
GHRP-6 ++++ ++ ++ ++++
GHRP-2 ++++ ++ +++ ++
Hexarelin +++++ +++ +++ +

Key Published Research

Year Focus Key Finding Reference
1998 Characterization Defined selectivity profile Raun et al.
2005 GH release Comparable to GHRP-6 for GH Johansen et al.
2008 Post-op recovery Phase II results in ileus Beck et al.
2011 Phase III trial Post-operative ileus results Greenwood et al.

Potential Benefits Under Investigation

Research Areas

  • Body composition optimization
  • Recovery and healing support
  • Age-related GH decline
  • Sleep quality (GH released during sleep)
  • Bone density maintenance

Administration in Research

Typical research parameters:

  • Route: Subcutaneous injection
  • Research doses: 100-300 mcg
  • Frequency: Often 2-3 times daily in studies
  • Timing: Pre-meal and/or before bed
  • Half-life: Approximately 2 hours

Safety Considerations

Based on available research data:

  • Generally well-tolerated in clinical trials
  • Common effects: injection site reactions, transient flushing
  • No significant hormonal disruption (cortisol, prolactin)
  • Long-term safety data limited

Research Status

Ipamorelin is not approved by the FDA for any indication. While it underwent clinical trials for post-operative ileus, development was discontinued. It remains available only as a research compound. All use should be under appropriate research protocols and oversight.

Summary

Ipamorelin stands out among growth hormone secretagogues for its selectivity and cleaner hormonal profile. By stimulating GH release without significantly affecting cortisol, prolactin, or appetite, it offers researchers a more targeted tool for studying GH-related effects. Its synergy with GHRH analogs has made the ipamorelin + CJC-1295 combination one of the most studied GH-enhancing protocols in research settings.

โ† Tesamorelin Research Next: CJC-1295 โ†’