Ipamorelin

The Selective Growth Hormone Secretagogue

Ipamorelin is a synthetic pentapeptide and highly selective agonist of the ghrelin/growth hormone secretagogue receptor (GHS-R1a). Originally developed by Novo Nordisk in the late 1990s, ipamorelin represents the first growth hormone-releasing peptide (GHRP) that selectively stimulates GH release without significantly affecting cortisol, prolactin, or ACTH levels.

This unique selectivity profile—mimicking the specificity of native GHRH rather than other GHRPs—has made ipamorelin particularly valuable for isolated GH research.

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Why Selectivity Matters

Ipamorelin's hormone profile distinguishes it from other growth hormone secretagogues:

Hormone	GHRP-6	GHRP-2	Ipamorelin
Growth Hormone	Increased	Increased	Increased
Cortisol	Increased	Increased	No significant effect
ACTH	Increased	Increased	No significant effect
Prolactin	Variable	Variable	No significant effect
Ghrelin-like appetite	Strong	Moderate	Minimal

This selectivity enables research into isolated GH effects without confounding hormonal changes.

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Research Focus Areas

Ipamorelin is being studied for its potential effects on:

• Growth hormone release — selective pulsatile GH stimulation
• Body composition — lean mass increase and fat reduction
• Bone metabolism — longitudinal bone growth and density
• Sleep quality — GH-mediated sleep architecture effects
• Muscle recovery — protein synthesis and tissue repair
• Metabolic function — glucose metabolism and insulin potentiation
• Anti-aging — IGF-1 axis optimization

Clinical trials evaluated ipamorelin for postoperative ileus but discontinued development; research continues in other applications.

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Clinical Development Context

• Developer: Novo Nordisk
• Phase: Phase II completed (postoperative ileus); discontinued
• Trial indication: Gastrointestinal motility disorders
• Regulatory status: Not FDA approved; WADA prohibited substance

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Technical Specifications

• Synonyms: NNC 26-0161
• Class: Growth hormone secretagogue / GHRP
• Sequence: Aib-His-D-2-Nal-D-Phe-Lys-NH₂
• Molecular Formula: C₃₈H₄₉N₉O₅
• Molecular Weight: 711.85 g/mol
• Form: Sterile lyophilized powder
• Half-life: ~2 hours

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Storage & Handling

• Lyophilized: Store at -20°C
• Reconstituted: Store at 2–8°C
• Protect from light and moisture
• Avoid repeated freeze-thaw cycles

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