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What Is Ipamorelin? Benefits, Research & Safety
A selective growth hormone-releasing peptide known for its favourable side effect profile, stimulating GH release without significantly affecting cortisol or prolactin.
Also known as:
NNC 26-0161
IPA
Educational Content Only: This page provides research-based information for educational purposes. Ipamorelin is not an approved medicine. This is not medical advice. Always consult a qualified healthcare professional.
Quick Facts
Category
Hormonal & Endocrine
Half-Life
Approximately 2 hours
UK Status
Not licensed for human use. Research compound only.
EU Status
Not approved for therapeutic use.
Overview
Ipamorelin is a pentapeptide (five amino acids) growth hormone-releasing peptide (GHRP) that stimulates growth hormone secretion from the pituitary gland. Developed by Novo Nordisk, it is notable for its high selectivity—it releases GH without significantly affecting other hormones like cortisol, prolactin, or ACTH.
Unlike other GHRPs such as GHRP-2 and GHRP-6, Ipamorelin produces a more targeted GH release with fewer side effects. It does not cause the significant hunger increase seen with GHRP-6 (which stimulates ghrelin receptors associated with appetite), making it more tolerable for many users.
Ipamorelin works through the ghrelin/growth hormone secretagogue receptor (GHS-R), triggering the pituitary to release growth hormone in a pulsatile manner similar to natural physiology. It is often combined with CJC-1295 (without DAC) for synergistic effects.
Despite its favourable profile, Ipamorelin is not approved for therapeutic use. Novo Nordisk discontinued clinical development, and it remains a research compound. It is prohibited in competitive sports.
Discovery & History
Ipamorelin was developed by Novo Nordisk in the 1990s as part of the company's research into growth hormone secretagogues. The goal was to develop compounds that could stimulate natural GH release as an alternative to direct GH replacement therapy.
Ipamorelin was designed to be more selective than earlier GHRPs like GHRP-6 and GHRP-2, which, while effective at releasing GH, also affected other hormonal systems. Studies confirmed that Ipamorelin was highly selective for GH release.
Clinical trials were conducted for various indications, and the peptide showed efficacy in stimulating GH release. However, Novo Nordisk ultimately discontinued development—reportedly due to strategic business decisions rather than safety or efficacy concerns.
Despite the lack of continued pharmaceutical development, Ipamorelin has become one of the most popular research peptides due to its selective action and favourable side effect profile. It is frequently combined with GHRHs like CJC-1295 in research protocols.
Mechanism of Action
Ipamorelin works through the ghrelin receptor to stimulate GH release:
**GHS Receptor Activation**
Ipamorelin binds to and activates the growth hormone secretagogue receptor (GHS-R, also called the ghrelin receptor) on pituitary somatotroph cells. This triggers intracellular signalling cascades that result in growth hormone release.
**Selective GH Release**
Unlike other GHRPs, Ipamorelin does not significantly stimulate ACTH, cortisol, or prolactin release. This selectivity results from its specific receptor binding properties and makes it better tolerated than less selective alternatives.
**Pulsatile GH Release**
Ipamorelin stimulates GH release in a pulsatile manner, mimicking the natural pattern of GH secretion. This may be more physiologically appropriate than sustained GH elevation.
**Minimal Appetite Stimulation**
While Ipamorelin works through the ghrelin receptor, it does not produce the significant appetite increase seen with GHRP-6. This may be related to different receptor activation kinetics or downstream signalling.
**Synergy with GHRH**
Ipamorelin is often combined with CJC-1295 without DAC (Mod GRF 1-29). The GHRH analogue primes the pituitary for GH release, while Ipamorelin triggers the release—resulting in synergistic effects.
[Molecular Structure Diagram Placeholder]
Researched Benefits
Based on preclinical and clinical research findings:
- 1Selective growth hormone release from the pituitary
- 2Elevated IGF-1 levels
- 3Minimal effect on cortisol and prolactin (unlike other GHRPs)
- 4No significant appetite increase (unlike GHRP-6)
- 5Potential improvements in body composition
- 6Possible enhancement of recovery and tissue repair
- 7Good tolerability profile
Theoretical Dosing & Protocols
⚠️ Educational Only: The following information is derived from research literature and is not a prescription or recommendation. No standardised human dosing exists. Always consult a qualified healthcare professional.
| Theoretical Dosage | 100-300 mcg per dose |
| Frequency | 2-3 times daily, typically before meals and at bedtime |
| Duration | Variable; often cycled or used for extended periods |
| Notes | Ipamorelin is not approved for human use. It is often combined with CJC-1295 without DAC for synergistic effects. Any use should be under medical supervision. |
Administration Routes
Routes studied in research settings (educational only):
- Subcutaneous injection (most common)
| Half-Life | Stability |
|---|---|
| Approximately 2 hours | Lyophilised powder should be stored refrigerated or frozen; reconstituted solution refrigerated |
Safety Profile & Known Risks
Commonly Reported Side Effects
- Injection site reactions
- Transient headache
- Mild water retention
- Tingling or numbness (less common than with GHRP-6)
Rare Risks & Concerns
- Unknown long-term effects
- Potential effects on glucose metabolism with prolonged use
- Theoretical concerns about tumour growth (applies to all GH-releasing agents)
Contraindications
- Active malignancy or history of cancer
- Pregnancy and breastfeeding
- Diabetes (monitor glucose closely)
- Children and adolescents (except under specialist care)
UK & EU Regulatory Context
🇬🇧 United Kingdom
Not licensed for human use. Research compound only.
🇪🇺 European Union
Not approved for therapeutic use.
Ipamorelin is not approved by any regulatory authority. It is prohibited in competitive sports by WADA. Clinical development was discontinued by Novo Nordisk.
Clinical Studies Summary
Ipamorelin: First Selective Growth Hormone Secretagogue
Research characterising Ipamorelin's selective GH-releasing properties compared to other GHRPs.
Eur J Endocrinol. 1999;141(6):580-8View on PubMed
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