Ipamorelin Peptide: the selective secretagogue
Ipamorelin peptide is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) that acts on the ghrelin receptor GHS-R1a to stimulate growth hormone release. In the study that characterised it, ipamorelin was described as the first selective growth hormone secretagogue because it released GH without markedly raising ACTH or cortisol in animal models (Raun et al., 1998). Researchers looking to buy ipamorelin for laboratory work can find ≥98% purity, HPLC-tested vials here — research use only.
Specifications
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 (5 amino acids) |
|---|---|
| Class | Growth hormone secretagogue (ghrelin mimetic) |
| CAS number | 170851-70-4 |
| Receptor target | GHS-R1a (ghrelin receptor) |
| Purity | ≥98% (HPLC) |
| Form | Lyophilised powder |
What is ipamorelin?
Ipamorelin belongs to the growth hormone secretagogue class — small peptides that mimic ghrelin at the GHS-R1a receptor in the pituitary and hypothalamus, triggering the body's own GH release rather than supplying GH directly.
Its distinguishing feature in the literature is selectivity: in the characterising animal studies it raised GH without the ACTH and cortisol increases seen with earlier secretagogues such as GHRP-6 (Raun et al., 1998).
Structure and stability
The sequence is Aib-His-D-2-Nal-D-Phe-Lys-NH2 — five residues, several of them non-natural. Aib (2-aminoisobutyric acid) and the D-configured residues resist protease cleavage, and the C-terminal amide removes a free carboxyl terminus.
These modifications are why a peptide this short survives long enough to be usable in a model system; an all-L pentapeptide of the same sequence would be degraded far more quickly.
The GHS-R1a pathway
GHS-R1a is the receptor for ghrelin. Activation on pituitary somatotrophs signals through the Gq/phospholipase C route, raising intracellular calcium and triggering GH release — a different second-messenger pathway from the cAMP route used by GHRH analogs.
Because the two pathways are separate but converge on the same cell, GHRH analogs and ghrelin mimetics are frequently studied together rather than as alternatives.
What the published study established
Raun et al. (1998) characterised ipamorelin in rats and swine, reporting dose-dependent GH release with no marked rise in ACTH, cortisol or prolactin at GH-releasing doses — the basis for calling it the first selective GH secretagogue.
This is preclinical work. It establishes a selectivity profile in animal models; it is not a human outcome trial.
- Models: rat and swine.
- Primary readout: GH release, with ACTH, cortisol and prolactin measured alongside.
- Claim supported: selectivity relative to earlier GHRPs.
What has not been established
There are no randomised human outcome trials of ipamorelin cited in this guide. Body-composition, recovery or performance claims are not supported by the evidence base described here, and ipamorelin is not an approved medicine in any jurisdiction.
Why ipamorelin is paired with CJC-1295
CJC-1295 is a GHRH analog acting on the GHRH receptor; ipamorelin acts on the ghrelin receptor. Because they stimulate GH release through two different receptors, researchers study them in combination, and the CJC-1295 (no DAC) + ipamorelin blend is one of the most-researched pairings in this class.
The pairing rests on component evidence and a receptor-level rationale — no controlled study of the commercial blend itself is cited here. See the CJC-1295 vs Ipamorelin comparison for details.
Interpreting the evidence in laboratory research
GH release is pulsatile, so a single blood or media timepoint can miss or exaggerate an effect. Serial sampling or an integrated measure is more informative, and IGF-1 is often used as a slower downstream proxy.
Receptor expression in the chosen model, and whether the model retains intact somatostatin feedback, both shape what a GH readout means.
Handling in the lab
Store lyophilised vials cold, dry and away from light. Reconstitute with bacteriostatic water using sterile technique, refrigerate the solution, and aliquot to avoid repeated freeze-thaw cycles. See the reconstitution and storage guides for details.
Frequently asked questions
What is ipamorelin peptide?
A synthetic five-amino-acid growth hormone secretagogue that acts on the ghrelin receptor GHS-R1a. It was characterised as the first selective GH secretagogue because it released GH without markedly raising ACTH or cortisol in animal studies.
What is the ipamorelin sequence?
Aib-His-D-2-Nal-D-Phe-Lys-NH2 — five residues including non-natural amino acids that resist protease breakdown.
How does ipamorelin trigger GH release?
By activating GHS-R1a on pituitary somatotrophs, which signals through phospholipase C and raises intracellular calcium, prompting release of stored GH.
What does selective mean for ipamorelin?
In the characterising animal studies it raised GH without a marked rise in ACTH, cortisol or prolactin, unlike earlier GHRPs such as GHRP-6.
Was ipamorelin tested in humans?
No randomised human outcome trials are cited in this guide. The published characterisation was in rat and swine models.
Is ipamorelin an approved medicine?
No. It is supplied here strictly for laboratory research.
How is ipamorelin different from tesamorelin?
Ipamorelin acts on the ghrelin receptor; tesamorelin is a GHRH analog acting on the GHRH receptor. They reach GH release through two different pathways.
How is ipamorelin different from CJC-1295?
Same distinction — CJC-1295 is a GHRH analog; ipamorelin is a ghrelin mimetic. They are structurally unrelated.
Why is ipamorelin sold in a blend with CJC-1295?
CJC-1295 (no DAC) and ipamorelin stimulate GH release through two different receptors, so researchers study them together. The blend is sold for laboratory research only.
Product pages: Ipamorelin 5mg / 10mg · CJC-1295 / Ipamorelin blend · Tesamorelin + Ipamorelin blend
Is there a study of the blend itself?
No controlled study of the combined formulation is cited here; the rationale is receptor-level and rests on component evidence.
How should GH be measured in ipamorelin research?
GH is released in pulses, so serial sampling or an integrated measure is more informative than a single timepoint; IGF-1 is commonly used as a downstream proxy.
Where can I buy ipamorelin peptide for research?
PeptidesDirect sells ipamorelin in 5mg and 10mg vials, plus CJC-1295/ipamorelin and tesamorelin/ipamorelin blends, for laboratory research only. Orders placed before 1:00 PM Central on business days ship the same day. See our research peptides guide research peptides guide for how to compare suppliers and read test documents.
Product pages: Ipamorelin 5mg / 10mg · CJC-1295 / Ipamorelin blend · Tesamorelin + Ipamorelin blend
How should ipamorelin be stored?
Keep lyophilised ipamorelin cold, dry and away from light; refrigerate reconstituted solutions. See our research peptides guide research peptides guide for how to compare suppliers and read test documents.
Is this product for human use?
No. PeptidesDirect sells this compound for laboratory research only. It is not a drug, food or cosmetic and is not for human or veterinary use. This page summarises published research and is not dosing or medical guidance.
Shop the compounds covered in these FAQs: Ipamorelin 5mg / 10mg · CJC-1295 / Ipamorelin blend · Tesamorelin + Ipamorelin blend
References
- Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998. PubMed 9849822
- Teichman SL, et al. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab. 2006. PubMed 16352683
- Ionescu M, Frohman LA. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. J Clin Endocrinol Metab. 2006. PubMed 17018654
Research compounds
Related guides
- CJC-1295 vs Ipamorelin
- Tesamorelin vs Ipamorelin
- GH peptide comparison
- Research peptides guide
- Reconstitution guide
- Storage guide
Research Use Only. Not for human or veterinary use. Not dosing or medical guidance.
