Research Guides

Ipamorelin Peptide: Research Guide (Aib-His-D-2-Nal-D-Phe-Lys-NH₂)

By UK Peptide Lab Research Team•19 September 2026•5 min read
Ipamorelin Peptide: Research Guide (Aib-His-D-2-Nal-D-Phe-Lys-NH₂) · research peptide

Key Takeaways

  • Ipamorelin is the pentapeptide Aib-His-D-2-Nal-D-Phe-Lys-NH₂ (711.85 g/mol, CAS 170851-70-4), developed at Novo Nordisk and characterised as the first selective growth hormone secretagogue (Raun et al., Eur J Endocrinol, 1998).
  • Selectivity is the experimental point: GH release comparable to GHRP-6 without the significant ACTH and cortisol responses seen with GHRP-2 and GHRP-6, even at multiples more than 200-fold above the GH-releasing ED₅₀.
  • It acts at GHS-R1a, cloned by Howard et al. (Science, 1996) and later identified as the receptor for ghrelin (Kojima et al., Nature, 1999).
  • Ipamorelin holds no marketing authorisation in any jurisdiction and its clinical development was discontinued. Supplied for in-vitro laboratory research only, with no dosing information and no human-use claims.

What is Ipamorelin?

Ipamorelin is a synthetic pentapeptide with the sequence Aib-His-D-2-Nal-D-Phe-Lys-NH₂, a molecular weight of 711.85 g/mol and CAS number 170851-70-4. Developed at Novo Nordisk and reported by Raun and colleagues (Eur J Endocrinol, 1998), it was characterised as the first selective growth hormone secretagogue: a pentapeptide that stimulates growth hormone release through GHS-R1a without the off-target hormone release of the earlier GHRP peptides. UK Peptide Lab supplies Ipamorelin 10mg, the higher-mass research format of our 5mg vial, as lyophilised powder for in-vitro laboratory use only.

Selectivity: The Point of the Molecule

The GHRP family began with GHRP-6 (His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂), a potent GH releaser that also raises ACTH, cortisol and prolactin, and GHRP-2 shares that off-target profile. Ipamorelin matched GHRP-6 for GH release while producing no significant ACTH or cortisol response in swine, even at multiples more than 200-fold above its GH-releasing ED₅₀ (Raun et al., Eur J Endocrinol, 1998). The receptor it acts through was cloned by Howard and colleagues (Science, 1996) and identified as the target of endogenous ghrelin by Kojima and colleagues (Nature, 1999).

Research Applications

Ipamorelin serves as the standard selective agonist control in GHS-R1a pharmacology: receptor binding studies, cAMP and calcium-mobilisation assays in receptor-transfected cell lines, and pulsatile GH release kinetics. Because it activates the GH axis without simultaneous HPA-axis activation, it suits designs where the question is GH biology uncontaminated by cortisol or ACTH release; where the GH and ACTH interplay is itself the endpoint, GHRP-2 or GHRP-6 are the appropriate tools. Johansen and colleagues (Growth Horm IGF Res, 1999) reported longitudinal bone growth in rats.

The 10mg Research Format

The 10mg vial holds twice the lyophilised mass of the 5mg vial and the identical compound. At a fixed fill volume the reconstituted stock is twice as concentrated, so fill volume must be scaled to the concentration your protocol specifies; we provide no dosing information. The larger vial suits high-throughput work: dose-response matrices and long time-course designs benefit from one batch under one certificate of analysis and a lower cost per milligram, since vial, stopper, lyophilisation and assay costs fall per vial rather than per milligram.

Reading the Evidence Honestly

Ipamorelin is a well-characterised laboratory tool, but its clinical history is short: a development programme, including work toward a postoperative ileus indication, was discontinued, and the compound holds no marketing authorisation in any jurisdiction. The human data consist of pharmacokinetic studies such as Gobburu and colleagues (Pharm Res, 1999); no therapeutic outcome data exist. This guide therefore carries no dosing information, no human-use claims and no outcome promises, and the material is supplied for in-vitro laboratory research only.

Laboratory Handling and Sourcing in the UK

Store lyophilised vials at -20°C, protected from light and moisture. Reconstitute by injecting bacteriostatic water slowly down the inner glass wall, never onto the powder, and swirl gently; never shake or vortex. Ipamorelin contains no methionine, cysteine or tryptophan, so sterility rather than oxidation is the practical constraint; hold the reconstituted solution at 2-8°C and use within approximately 4 weeks, aliquoting for anything longer. UK Peptide Lab supplies research-grade Ipamorelin 10mg at £29.99, supplier-tested, with the supplier certificate published on the product page and independent third-party verification pending. Same-day UK dispatch on orders placed before 2pm GMT, free Royal Mail Tracked shipping over £45. For in-vitro laboratory research use only, not for human consumption.

Related Products

Ipamorelin Ipamorelin CJC-1295 GHRP-2 Bacteriostatic Water

Disclaimer: This article is for research and educational purposes only. All information provided is not intended as medical advice. UK Peptide Lab products are not for human consumption and are sold strictly for laboratory research use only.

Frequently Asked Questions

What is Ipamorelin?

Ipamorelin is a synthetic pentapeptide with the sequence Aib-His-D-2-Nal-D-Phe-Lys-NH₂, molecular weight 711.85 g/mol and CAS 170851-70-4. It was developed at Novo Nordisk and reported by Raun and colleagues (Eur J Endocrinol, 1998) as the first selective growth hormone secretagogue, acting through the ghrelin receptor GHS-R1a. It is supplied as lyophilised powder for in-vitro laboratory research only and holds no marketing authorisation in any jurisdiction.

How selective is Ipamorelin?

In the original characterisation, ipamorelin stimulated GH release with potency and efficacy comparable to GHRP-6 while producing no significant ACTH or cortisol response in swine, even at multiples more than 200-fold above its GH-releasing ED₅₀ (Raun et al., Eur J Endocrinol, 1998). GHRP-2 and GHRP-6 raise ACTH, cortisol and prolactin in the same models, which is why ipamorelin is the selective control in GHS-R1a research.

How does the 10mg vial differ from the 5mg vial?

Only in content. It is the identical pentapeptide at twice the mass per vial, with its own batch number and its own certificate of analysis. At a fixed reconstitution volume it reaches twice the concentration, so fill volume must be scaled to the concentration your protocol specifies. We provide no dosing information. Research use only.

References

  1. [1] Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol (1998). View →
  2. [2] A receptor in pituitary and hypothalamus that functions in growth hormone release. Science (1996). View →
  3. [3] Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature (1999). View →
  4. [4] Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats. Growth Horm IGF Res (1999). View →
  5. [5] Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharm Res (1999). View →

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