Ipamorelin is a synthetic pentapeptide that has been found to have specific growth hormone (GH)-releasing properties. As a growth hormone secretagogue, it stimulates the release of growth hormone from the pituitary gland, resulting in increased muscle mass, reduced body fat, and improved bone density.

The peptide sequence of Ipamorelin is able to bind to the ghrelin/growth hormone secretagogue receptor, making it one of the most specific GH secretagogues currently known. Studies have shown that it has no effect on cortisol release, follicle-stimulating or luteinizing hormone, thyroid-stimulating hormone, or ACTH.

Ipamorelin's high level of selectivity has made it a subject of great interest in research, as it can serve as a therapeutic agent and a model peptide to uncover the mechanisms behind receptor binding selectivity.

In a study conducted on adult female rats, different doses of Ipamorelin (0, 18, 90, and 450 microg/day) were administered three times a day for 15 days to investigate its effects on longitudinal bone growth rate (LGR), body weight (BW), and GH release. The results showed that Ipamorelin dose-dependently increased LGR from 42 microm/day in the control group to 44, 50, and 52 microm/day in the treatment groups (P<0.0001). There was also a dose-dependent effect on BW gain, but no effect on total IGF-I levels, IGFBPs, or serum markers of bone formation and resorption.