Ipamorelin

Ipamorelin research peptide in Thailand

Ipamorelin is a synthetic pentapeptide growth hormone secretagogue that acts as an agonist at the ghrelin receptor (GHS-R1a), studied for its unusually selective growth hormone release — it was characterised as the first GH secretagogue that raises GH without significantly elevating ACTH or cortisol (Raun, Eur J Endocrinol, 1998).

This listing is for laboratory research use only. The evidence base is largely preclinical, with a small number of early-phase human pharmacokinetic and Phase 2 studies; it is not a medicine, supplement, or performance product.

Quick facts

Product

Ipamorelin (standalone, not a CJC-1295 blend)

CAS

170851-70-4

Molecular weight

~711.9 g/mol

Form

Lyophilised powder, sealed vial

Intended use

laboratory research use only

How Ipamorelin works

Ipamorelin binds the growth hormone secretagogue receptor (GHS-R1a) on somatotroph cells of the anterior pituitary — the same receptor targeted by the endogenous hormone ghrelin. GHS-R1a is Gq-coupled, so activation drives phospholipase C signalling and a rise in intracellular calcium, which triggers exocytosis of stored growth hormone granules. The result described in the literature is a discrete, pulsatile GH release rather than a sustained elevation.

What distinguishes ipamorelin in the published record is its receptor selectivity. Earlier peptidyl secretagogues such as GHRP-2 and GHRP-6 also stimulate ACTH and cortisol release; in the original characterisation study, ipamorelin released GH with potency comparable to GHRP-6 in rat pituitary cells, anaesthetised rats, and conscious swine, yet did not release ACTH or cortisol at levels significantly different from GHRH stimulation (Raun, Eur J Endocrinol, 1998). That separation is why it appears so often as a control or comparator compound in GH-axis work. Note that GHS-R1a agonism is a distinct mechanism from the GHRH-receptor route used by CJC-1295 (no DAC) and tesamorelin.

Key research findings

• In its original characterisation, ipamorelin released GH with a potency and efficacy comparable to GHRP-6 across rat pituitary cells, anaesthetised rats, and conscious swine, but did not release ACTH or cortisol at levels significantly different from those seen with GHRH (Raun, Eur J Endocrinol, 1998).
• In a human dose-escalation study across five infusion rates, ipamorelin showed dose-proportional pharmacokinetics with a terminal half-life of 2 hours, clearance of 0.078 L/h/kg, and a single episodic GH release peaking at ~0.67 hours (Gobburu, Pharm Res, 1999).
• In a randomised, controlled Phase 2 proof-of-concept trial in 117 bowel-resection patients, ipamorelin was well tolerated but did not differ significantly from placebo on the key or secondary efficacy endpoints for postoperative ileus (Beck, Int J Colorectal Dis, 2014).
• In adult female rats, ipamorelin produced a dose-dependent increase in longitudinal bone growth rate (42 to 52 µm/day at the highest dose, P<0.0001) without altering total IGF-I or IGF-binding protein levels (Johansen, Growth Horm IGF Res, 1999).

Research applications

• GHS-R1a receptor pharmacology and secretagogue selectivity studies
• Pulsatile GH secretion and pituitary somatotroph signalling models
• Comparator/control compound in GHRP-2 and GHRP-6 cortisol-confounding work
• Bone formation and glucocorticoid-catabolism models in rodents
• Gastrointestinal motility and postoperative ileus models
• Cross-mechanism GH-axis studies alongside GHRH-receptor analogues

Dosing in the literature

The human dose-escalation study infused 4.21–140.45 nmol/kg over 15 minutes rather than administering fixed amounts (Gobburu, Pharm Res, 1999), and the rodent work used roughly 0.1–1 mg/kg per administration. These figures are a summary of parameters as reported in published research, not administration guidance. To model concentrations for a defined protocol, use the Ipamorelin peptide calculator.

Reconstitution & storage

Solvent

Bacteriostatic water — standard for lyophilised research peptides

Mixing

Add solvent down the vial wall and swirl gently until dissolved; do not shake

Storage

Refrigerated (2–8 °C) after reconstitution, in common laboratory practice

Use within

A few weeks once reconstituted

Freeze / light

Keep lyophilised powder frozen or cold, sealed, and protected from light

This describes common laboratory handling practice for lyophilised peptides, not preparation instructions. In Thailand's heat and humidity, protect vials from ambient temperature swings during storage and courier handling, and minimise time spent out of cold storage.

Selected research

• Ipamorelin, the first selective growth hormone secretagogue — Eur J Endocrinol, 1998
• Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers — Pharm Res, 1999
• Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients — Int J Colorectal Dis, 2014
• The growth hormone secretagogue ipamorelin counteracts glucocorticoid-induced decrease in bone formation of adult rats — Growth Horm IGF Res, 2001
• Browse all indexed ipamorelin literature on PubMed

Related compounds

• CJC-1295 (no DAC) — a short-acting GHRH analogue. It reaches the same pituitary somatotrophs through the GHRH receptor rather than GHS-R1a, which is why the two are frequently studied as complementary arms of the GH axis.
• Tesamorelin — a stabilised GHRH analogue with the most developed human clinical record on this axis, useful as a reference comparator in GH/IGF-1 study design.
• Bacteriostatic water — the standard diluent used to reconstitute lyophilised research peptides.

See also: growth hormone secretagogues compared and more growth-hormone-axis compounds.

Ipamorelin FAQ

Compliance note

Ipamorelin is supplied for laboratory research use only. It is not for human or veterinary use, and it is not intended to diagnose, treat, cure, or prevent any disease. All findings referenced above are the results of specific published studies, not claims about this product.