IPAMORELIN (GHRP)

Mechanism of Action
Ipamorelin is a growth hormone (GH) secretagogue and a selective agonist of the ghrelin receptor (GHSR-1a). It is a synthetic pentapeptide derived from GHRP-1 that significantly increases plasma GH levels in both animals and humans. Unlike other GH-releasing peptides (e.g., GHRP-2 or GHRP-6), ipamorelin does not stimulate the release of ACTH or cortisol, nor does it alter other hormones (prolactin, FSH, LH, TSH), demonstrating high selectivity for inducing GH secretion only.
 
Known or Proposed Clinical/Therapeutic Uses
Ipamorelin was investigated for the treatment of postoperative ileus (a gastrointestinal motility disorder following surgery). In a phase II trial, ipamorelin (0.03 mg/kg i.v. twice daily) was well tolerated but did not significantly shorten gastrointestinal recovery time compared with placebo, leading to discontinuation of its development for this indication. It currently has no approved medical uses and remains primarily experimental. Ipamorelin has been used off-label in athletic and bodybuilding settings as a performance-enhancing agent to stimulate endogenous GH, with the aim of increasing muscle mass and improving body composition.
 
Side Effects or Associated Risks
Ipamorelin is generally well tolerated at commonly used doses. Reported adverse effects are mostly mild and transient, including injection-site reactions (pain, redness, swelling, or itching), temporary headache, nausea, dizziness or lightheadedness, increased appetite, mild fluid retention (peripheral edema), transient joint pain or stiffness, fatigue, and mild flu-like symptoms (low-grade fever, chills, myalgia). In rare cases, more severe or long-term effects may occur. Some studies suggest that chronic use of GH secretagogues such as ipamorelin could potentially increase the risk of certain diseases, reduce lifespan, or accelerate cellular aging processes, although these observations are preliminary. Additionally, as an exogenous peptide, there is a risk of immunogenicity (antibody formation or allergic reactions).