Ipamorelin

Ipamorelin is a synthetic pentapeptide that acts as a selective growth hormone secretagogue (GHS), stimulating the pituitary gland to release growth hormone by mimicking the action of ghrelin at the GHS receptor (GHS-R1a). Developed in the late 1990s, Ipamorelin was designed to provide targeted GH release without many of the side effects associated with other GH secretagogues like GHRP-6 and GHRP-2.

What distinguishes Ipamorelin from other GH secretagogues is its selectivity. While peptides like GHRP-6 can significantly increase cortisol, prolactin, and appetite (through strong ghrelin-mimetic effects), Ipamorelin produces GH release with minimal impact on these other hormones at therapeutic doses. This selectivity makes it one of the preferred GH-releasing peptides for clinical and research applications, as it avoids many unwanted side effects associated with broader hormonal stimulation.

In preclinical and clinical research, Ipamorelin has demonstrated dose-dependent increases in growth hormone release. Studies in both healthy volunteers and post-surgical patients have shown it can effectively stimulate GH secretion. Research in the context of postoperative ileus (delayed return of bowel function after surgery) explored its potential to accelerate gastrointestinal recovery, though this indication was not ultimately pursued commercially.

Ipamorelin is most commonly used in combination with CJC-1295 without DAC (Mod GRF 1-29), a pairing frequently offered at anti-aging and hormone optimization clinics. The rationale for this combination is that CJC-1295 stimulates GH release via the GHRH receptor while Ipamorelin acts through the ghrelin receptor, producing a synergistic amplification of the GH pulse that more closely resembles a robust physiological release pattern.