CJC-1295 vs Sermorelin: GHRH Analogues Compared
CJC-1295 and sermorelin are both GHRH analogues that stimulate pituitary GH release, but differ in half-life, DPP-IV resistance, and whether they preserve physiological GH pulsatility. This comparison reviews the key research differences.
CJC-1295 (without DAC) and Sermorelin are both GHRH-R agonists that produce pulsatile GH release — the same downstream effect through the same receptor. Their key difference is half-life, translating to different GH pulse widths and practical dosing requirements.
Molecular Differences and Half-Life
Sermorelin is GHRH 1-29 (29 amino acids). Half-life: ~10-12 minutes. It is susceptible to DPP-IV cleavage at the Ala²-Gln³ bond and other serum proteases.
CJC-1295 (no DAC) (also called modified GRF 1-29 or mod-GRF 1-29) has four amino acid substitutions (positions 2, 8, 15, and 27) that block DPP-IV cleavage and reduce protease susceptibility. Half-life: ~30 minutes — approximately 3× longer than sermorelin — with essentially identical GHRH-R binding affinity.
GH Pulse Profile
The longer half-life of CJC-1295 (no DAC) produces broader GH pulses: ~90-120 minutes above baseline vs ~60-75 minutes for sermorelin per injection. Total GH AUC per injection is correspondingly higher.
Both peptides maintain physiologically pulsatile GH release — distinct from CJC-1295 with DAC, which produces 8-10 days of continuous GHRH-R activation. The pulsatile distinction matters for axis physiology: continuous GH exposure leads to GH receptor desensitisation.
When Sermorelin Is Preferred
Sermorelin's 10-12 minute half-life most precisely mimics endogenous GHRH pulse kinetics (2-5 min hypothalamic pulses). For research specifically studying endogenous GHRH pulse physiology and downstream consequences, sermorelin's kinetics may be more appropriate. Sermorelin also has a longer clinical research history (former FDA approval for pediatric GH deficiency diagnosis) with an extensive safety and pharmacology reference base.
When CJC-1295 (No DAC) Is Preferred
For convenience and higher GH AUC per injection, CJC-1295 (no DAC) is preferred in most modern research protocols. Its DPP-IV resistance also makes it compatible with combination products. In combination with Ipamorelin, it is the most commonly studied GHRH analogue in modern peptide research.
Neither peptide is approved for general adult GH optimisation.
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Broader Secretagogue Context
CJC-1295 and sermorelin represent two ends of the GHRH half-life spectrum. Mod GRF 1-29 occupies the middle: identical to CJC-1295 without DAC, providing the bridging reference between the two. GHRP-6 and Hexarelin are the primary GHRH-synergistic partners used to amplify results in both CJC-1295 and sermorelin studies. Ghrelin, Somatostatin, and Somatropin (rHGH) form the endogenous reference triad for interpreting all GHRH analogue research outcomes. Tesamorelin adds the FDA-validated clinical anchor to this comparison.
About the Author
KnowYourPeptide Research Team
KnowYourPeptide Research Team
Content produced by the KnowYourPeptide research and editorial team. All articles are written from peer-reviewed primary literature and reviewed for scientific accuracy by credentialed researchers and a board-certified physician before publication.
Meet the full editorial teamMedically Reviewed by Dr. Amanda Reid, MD
This article has been reviewed by Dr. Amanda Reid, MD (Board-Certified Internal Medicine), Know Your Peptide Medical Advisor, for scientific accuracy, safety information, and appropriate clinical context. Learn about our review process.