Ipamorelin: Scientific Profile
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Synthetic pentapeptide (CAS 170851-70-4) selective agonist of the ghrelin receptor GHSR-1a and growth hormone secretagogue. It induces GH pulses without raising cortisol or prolactin. Reagent for research.
Ipamorelin (Ipamorelin Acetate; CAS 170851-70-4) is a synthetic pentapeptide of sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2 (formula C38H49N9O5, molecular weight 711.85 Da), classified as a growth hormone secretagogue (GHS) and a selective agonist of the ghrelin receptor (GHSR-1a). It was developed by Novo Nordisk in the late 1990s as a tool to study the pulsatile release of GH. Its distinctive feature is selectivity: in the literature, Ipamorelin induces growth hormone pulses without elevating cortisol or prolactin, unlike other secretagogues such as GHRP-2, GHRP-6 or hexarelin. It acts on pituitary somatotrophs and modulates, in a downstream manner, the GH/IGF-1 axis. It was evaluated in phase 2 clinical trials for postoperative ileus, without obtaining regulatory approval; it is not approved as a drug. Preclinical and in vitro research documents applications in the GH/IGF-1 axis, gastrointestinal motility and models of sarcopenia and cachexia. It is distributed as a lyophilized powder for research use (RUO).
Mechanism of action
Ipamorelin is a selective agonist of the ghrelin receptor GHSR-1a, a Gq/11 protein-coupled receptor expressed in the hypothalamus (arcuate nucleus, GHRH and AgRP neurons), the anterior pituitary (somatotrophs), and the gastrointestinal mucosa. Binding to GHSR-1a in somatotrophs activates the PLC → IP3 → release of intracellular Ca2+ → exocytosis of GH granules cascade, generating a GH release pulse of amplitude comparable to endogenous pulses. The selectivity of Ipamorelin for GHSR-1a (without activity on CRH, dopamine, or serotonin receptors) explains the absence of cortisol and prolactin elevation observed with other GHS. The stimulation is complementary and synergistic with endogenous GHRH: they act on distinct receptors but converge on GH release. Subcutaneous administration of 100-300 µg in humans induces a GH pulse peaking at 30-60 min and lasting 90-120 min. EC50 for GHSR-1a: ~1.3 nM. Plasma half-life: ~2 hours. Elimination by peptide catabolism, without CYP450 metabolism. It does not significantly cross the blood-brain barrier; its central effects are mediated by peripheral GHSR-1a in circumventricular organs.
Mechanism summary
Selective agonist of the ghrelin receptor (GHSR-1a) on pituitary somatotrophs; it induces pulsatile release of growth hormone without elevating cortisol or prolactin, with downstream modulation of the GH/IGF-1 axis.
Estudios Clínicos (10)
- Ipamorelin for postoperative ileus – Phase 2 study (Beck DE, Sweeney WB, McCarter MD, et al. · International Journal of Colorectal Disease · 2014) — Randomized phase 2 trial evaluating ipamorelin in the recovery of postoperative ileus after major abdominal surgery. PMID 25331030.
- Ipamorelin: The first selective growth hormone secretagogue (Raun K, et al. · European Journal of Endocrinology · 1998) — First study characterizing Ipamorelin as a selective GH secretagogue. PMID 9849822.
- Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. (Gobburu JV, et al. · Pharm Res · 1999) PMID 10496658.
- A new series of highly potent growth hormone-releasing peptides derived from ipamorelin (Ankersen, et al. · Journal of Medicinal Chemistry · 1998) PMID 9733495.
- Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone (Bowers, et al. · Journal of Clinical Endocrinology & Metabolism · 1990) PMID 2108187.
- Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog. (Jetté L, et al. · Endocrinology · 2005) PMID 15817669.
- 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. (Teichman SL, et al. · J Clin Endocrinol Metab · 2006) PMID 16352683.
- Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. (Ionescu M, et al. · J Clin Endocrinol Metab · 2006) PMID 17018654.
- Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. (Mendias CL, et al. · Sports Med · 2026) PMID 41966639.
- The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. (Dominikowski A, et al. · Front Endocrinol (Lausanne) · 2026) PMID 42395176.
Warnings
Ipamorelin is a compound exclusively for research use (RUO); the following warnings and handling considerations apply to its use in the laboratory:
- Experimental agent without regulatory approval
- Insulin resistance may worsen with chronic elevation of GH/IGF-1
- Theoretical risk of tumor promotion via IGF-1
- Possible carpal tunnel syndrome with prolonged use
- Monitor glucose, HbA1c and IGF-1 in chronic studies
- No long-term safety data (>12 months) in humans
- Active neoplasms
- Decompensated diabetes mellitus
- Proliferative retinopathy
- Hypersensitivity to the peptide
- Pregnancy and lactation (no data)
- Growing children and adolescents
Technical data
- CAS
- 170851-70-4
- Molecular formula
- C38H49N9O5
- Molecular weight
- 711.85 Da
- Compound type
- peptide
- Storage
- -20 °C liofilizado; 2-8 °C reconstituido
- Shelf life (lyophilized)
- 36 months at 2-8°C
- Shelf life (reconstituted)
- 14-21 days at 2-8°C with bacteriostatic preservative
- Light-sensitive
- Sí
Available for research
Ipamorelin is available as a research reagent (RUO) with HPLC-verified purity and COA per batch:
Frequently asked questions about Ipamorelin
What is Ipamorelin?
Synthetic pentapeptide (CAS 170851-70-4), a selective agonist of the ghrelin receptor GHSR-1a and a growth hormone secretagogue. It induces GH pulses without raising cortisol or prolactin.
What is the mechanism of action of Ipamorelin?
Selective agonist of the ghrelin receptor (GHSR-1a) on pituitary somatotrophs; it induces pulsatile release of growth hormone without elevating cortisol or prolactin, with downstream modulation of the GH/IGF-1 axis.
What is Ipamorelin researched for?
In preclinical research, Ipamorelin is studied primarily in: Research on pulsatile GH release; GH/IGF-1 axis models; Studies of sarcopenia and cachexia. Material exclusively for scientific research.
What are the chemical properties of Ipamorelin?
Molecular formula C38H49N9O5; molecular weight 711.85 Da; CAS number 170851-70-4.
How is Ipamorelin stored?
Condiciones de conservación: -20 °C liofilizado; 2-8 °C reconstituido; estabilidad liofilizado: 36 meses a 2-8°C; una vez reconstituido: 14-21 días a 2-8°C con conservante bacteriostático; protéjase de la luz.
What routes of administration are studied for Ipamorelin?
In the research models the following are described: Subcutaneous. Use is exclusively for scientific research.