Ipamorelin is a synthetic pentapeptide that operates as a selective growth hormone (GH) secretagogue. It has distinct properties that make it an interesting candidate for various therapeutic applications:

1. Growth Hormone Release:

   • Ipamorelin effectively stimulates the secretion of GH from the pituitary gland, influencing anabolic processes such as muscle growth, recovery, and fat metabolism¹².
   • Compared to other GH secretagogues such as GHRP-6, ipamorelin is noted for its specificity in releasing GH without significantly increasing levels of cortisol or adrenocorticotropic hormone (ACTH)³.

2. Bone Growth:

   • Studies have demonstrated that ipamorelin can induce longitudinal bone growth. In rodent models, it has shown a dose-dependent increase in bone growth rate without significantly affecting serum markers of bone formation and resorption¹.

3. Gastrointestinal Motility:

   • Ipamorelin acts on the ghrelin receptor, which also affects gastrointestinal motility. It has been found to improve gastric emptying in models of postoperative ileus, potentially offering therapeutic benefits for conditions involving delayed gastric emptying⁴⁵.

4. Insulin Secretion:

   • Research has indicated that ipamorelin can stimulate insulin release from the pancreas through calcium channel and adrenergic receptor pathways, showcasing its potential use in metabolic disorders⁶.

5. Adiposity and Weight Gain:

   • Ipamorelin has been shown to increase body weight and adiposity in GH-deficient and GH-intact mice. This weight gain was notable early in the treatment period and stabilized over time⁷.

6. Clinical Trials on Postoperative Ileus:

   • In clinical trials, ipamorelin has been administered to patients undergoing bowel resection surgeries. Although the trials demonstrated shorter times to return of gastrointestinal function, the results did not reach statistical significance compared to placebo⁸.

Footnotes

1. P B Johansen, "Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats," PubMed, 1999. ↩ ↩²

2. K Raun, "Ipamorelin, the first selective growth hormone secretagogue," PubMed, 1998. ↩

3. Deepankar K. Sinha, "Beyond the androgen receptor: the role of growth hormone secretagogues," NCBI, 2019. ↩

4. Beverley Greenwood-Van Meerveld, "Efficacy of ipamorelin on gastric dysmotility," NCBI, 2012. ↩

5. David E Beck, "Prospective study of ipamorelin for the management of postoperative ileus," PubMed, 2021. ↩

6. Ernest Adeghate, "Mechanism of ipamorelin-evoked insulin release," PubMed, 2024. ↩

7. Deepankar K. Sinha, "Beyond the androgen receptor: ipamorelin effect on body composition," NCBI, 2019. ↩

8. David E Beck, "Clinical trial of ipamorelin for postoperative ileus," PubMed, 2021. ↩