Research Reference · Growth-Hormone Axis
Ipamorelin
A selective five-amino-acid growth-hormone secretagogue studied for its targeted growth-hormone release, often discussed with CJC-1295.
At a glance
Ipamorelin is a five-amino-acid growth-hormone secretagogue — it triggers growth-hormone release through the ghrelin receptor. Its research reputation rests on selectivity: in the study that introduced it, it released growth hormone without raising ACTH or cortisol, even at very high doses. The evidence is mainly animal work plus early human pharmacology.
What it’s studied for
Not currently stocked
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How it works
Ipamorelin acts on the growth-hormone secretagogue receptor — the ghrelin receptor — in the pituitary. 5 In the 1998 study that introduced it, it released growth hormone with a selectivity similar to GHRH and did not raise ACTH or cortisol, even at doses more than 200-fold above those needed for growth-hormone release. 1
In rats it increased longitudinal bone growth, 3 and in a rodent model of postoperative ileus repeated administration improved gut output and food intake. 5 A human study modeled its pharmacokinetics and growth-hormone response in volunteers, 2 and an animal study looked at nasal absorption of it and related peptides. 4
It is often discussed alongside CJC-1295, which acts through the GHRH receptor instead.
Related research
Frequently asked questions
What makes Ipamorelin “selective”?
How does Ipamorelin work?
How is Ipamorelin different from CJC-1295?
What is the CAS number of Ipamorelin?
Do you sell Ipamorelin?
Identifiers
| Name | Ipamorelin |
|---|---|
| Development code | NNC 26-0161 |
| Class | Growth-hormone secretagogue (pentapeptide) |
| Sequence |
Aib-His-D-2-Nal-D-Phe-Lys-NH2 |
| Molecular formula | C38H49N9O5 |
| Molecular weight | 711.9 g/mol |
| CAS number | 170851-70-4 |
| PubChem CID · UNII | 9831659 · Y9M3S784Z6 |
Identifiers checked against PubChem (CID 9831659). The sequence uses non-standard amino acids (Aib, D-2-Nal).
Research timeline
Key studies
| Study | Model | What it found |
|---|---|---|
| Raun 1998 1 | Animal | GH release as selective as GHRH; no ACTH or cortisol rise even at >200× the effective dose. |
| Johansen 1999 3 | Rat | Increased longitudinal bone growth. |
| Gobburu 1999 2 | Human volunteers | PK/PD model of ipamorelin disposition and GH response across doses. |
| Venkova 2009 5 | Rat | Repeated administration improved fecal output, food intake and weight gain after surgery. |
Sources
- Ipamorelin, the first selective growth hormone secretagogue. Raun K, et al. Eur J Endocrinol, 1998.
- Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Gobburu JV, et al. Pharm Res, 1999. Human
- Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats. Johansen PB, et al. Growth Horm IGF Res, 1999.
- Pharmacokinetic evaluation of ipamorelin and other peptidyl growth hormone secretagogues with emphasis on nasal absorption. Johansen PB, et al. Xenobiotica, 1998.
- Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus. Venkova K, et al. J Pharmacol Exp Ther, 2009.
Last reviewed September 2026 by Midwest Compounds. Every source above was checked against its original publication.