Ipamorelin

Ipamorelin is a synthetic pentapeptide growth hormone secretagogue (GHS) that selectively stimulates growth hormone release from the pituitary gland. It was developed by Novo Nordisk and is considered one of the most selective GHRPs (growth hormone releasing peptides) available for research. Unlike other GHRPs such as GHRP-6 and GHRP-2, ipamorelin does not significantly affect cortisol, prolactin, or acetylcholine levels at normal doses. This selectivity is attributed to its specific interaction with the ghrelin/GHS receptor (GHSR) without activating other pathways that cause unwanted hormonal effects.

Ipamorelin's mechanism centers on the growth hormone secretagogue receptor: **GHSR-1a Activation:** Ipamorelin binds to the growth hormone secretagogue receptor (ghrelin receptor) in the pituitary, triggering a signaling cascade that results in GH release. The binding pattern is distinct from ghrelin itself, contributing to its selectivity. **Pulsatile GH Release:** Rather than causing a continuous elevation, ipamorelin stimulates GH release in a pulsatile manner that more closely mimics natural physiological patterns. This pulsatility is important for maintaining GH receptor sensitivity. **Minimal Side Effects:** Due to its selective receptor interaction, ipamorelin does not increase appetite (unlike GHRP-6), does not raise cortisol or prolactin, and does not affect heart rate or blood pressure at standard doses. **Dose-Dependent Response:** GH release follows a dose-dependent curve with saturation at higher doses, allowing for controlled and predictable responses in research settings.