GH Secretagogues

CJC-1295 is a synthetic peptide analogue of growth hormone-releasing hormone (GHRH), specifically a modified version of the first 29 amino acids of endogenous GHRH (GRF 1-29). The peptide incorporates four amino acid substitutions that confer resistance to enzymatic degradation by dipeptidyl peptidase IV (DPP-IV), which normally cleaves and inactivates native GHRH within minutes. CJC-1295 exists in two forms: with a Drug Affinity Complex (DAC) that binds serum albumin to extend half-life to approximately 6-8 days, and without DAC (commonly called Mod GRF 1-29) which retains a shorter half-life of roughly 30 minutes. The peptide was developed by ConjuChem Biotechnologies and reached Phase II clinical trials for growth hormone deficiency and lipodystrophy before development was discontinued. It remains one of the most studied GHRH analogues and is frequently used in research settings, often in combination with GH-releasing peptides (GHRPs) to produce synergistic GH release through dual receptor activation.

Ipamorelin is a synthetic pentapeptide growth hormone secretagogue (GHS) that stimulates pituitary growth hormone (GH) release through agonism of the ghrelin/GHS-R1a receptor. Developed by Novo Nordisk in the late 1990s, it was the first GHS demonstrated to selectively release GH without concomitant stimulation of ACTH, cortisol, or prolactin at physiological doses. This selectivity profile distinguishes it from earlier GHS peptides such as GHRP-6 and hexarelin. Ipamorelin has been investigated in human clinical trials, most notably a Phase II study for postoperative ileus following abdominal surgery. While it demonstrated a favorable safety profile in that context, it did not meet its primary efficacy endpoint and development for that indication was not advanced. It remains of significant research interest as a tool compound for studying GH axis physiology and as a potential therapeutic in age-related GH decline.