Ipamorelin
Research Overview · Mechanism of Action · Reconstitution Guide
Overview
Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH₂) and selective growth hormone secretagogue (GHS). It was developed as a highly selective ghrelin receptor (GHSR-1a) agonist with minimal off-target activity at cortisol, prolactin, or ACTH pathways — a key distinction from earlier GHRPs. Ipamorelin has a molecular weight of 711.9 Da and is among the most studied selective GH secretagogues in preclinical research.
Mechanism of Action
Ipamorelin binds and activates the GHSR-1a (ghrelin receptor) on somatotroph cells in the anterior pituitary, stimulating GH release via phospholipase C / IP3 / intracellular calcium signaling. Unlike GHRP-2 and GHRP-6, ipamorelin does not significantly stimulate cortisol or prolactin release at research doses, suggesting high receptor selectivity. GH release is pulsatile and synergistic with endogenous GHRH. Downstream effects include hepatic IGF-1 production, lipolysis, and anabolic signaling in muscle and bone.
Key Studies & References
Raun K et al. (1998). Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol 139:552–561. Foundational characterization study.
Bowers CY (2004). Unnatural growth hormone-releasing peptide begets natural ghrelin. J Clin Endocrinol Metab 89:4901–4904.
Johansen PB et al. (1999). Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats. Growth Horm IGF Res 9:106–113.
Bacteriostatic Water Reconstitution Guide
Research Use Only — The following reconstitution information is provided for in vitro laboratory research purposes only. Not for human or veterinary use.
Recommended Solvent
Bacteriostatic water (0.9% benzyl alcohol)
Standard Volume
Add 2 mL bacteriostatic water to a 2 mg vial to yield a 1000 mcg/mL solution. For a 5 mg vial, add 5 mL for a 1000 mcg/mL solution.
Working Concentration
1000 mcg/mL is the standard working concentration for research.
Storage (Reconstituted)
Reconstituted: 2–8°C, use within 28 days. Lyophilized: -20°C, desiccated.
Stability Window
Stable for 28 days at 2–8°C. Ipamorelin is relatively stable in solution.
Technique
Inject bacteriostatic water slowly along the vial wall. Swirl gently until dissolved. Ipamorelin dissolves quickly — typically within 30 seconds.
Notes
As a small pentapeptide, ipamorelin is highly soluble and stable. Bacteriostatic water is preferred for multi-use research vials.
Research Dosing Reference
The following dosing information is derived from published preclinical research literature and is provided for reference purposes only.
Clinical / Human Research Range
Phase II trials used 200 mcg subcutaneous three times daily. No approved clinical indication.
Preclinical Models
Rodent studies: 100–300 mcg/kg subcutaneous. Effective GH pulse stimulation observed at 100 mcg/kg in rats.
Calculation Example
For a 1000 mcg/mL solution: a 200 mcg research dose = 0.2 mL (20 units on a 100-unit insulin syringe).