CJC-1295 vs Sermorelin

CJC-1295 (no DAC) and Sermorelin are both full agonists at the GHRH receptor (GHRHR) and raise growth hormone through the identical cAMP-mediated pathway — the difference between them is structural stability and duration of receptor activation. Sermorelin is the full 44-amino-acid GHRH 1–44 sequence (molecular weight 3,357.9 Da) with a half-life of approximately 10–20 minutes. CJC-1295 without DAC (Modified GRF 1-29) is a 29-amino-acid sequence (molecular weight 3,367.9 Da) with four amino acid substitutions that resist enzymatic degradation, extending its half-life to roughly 30 minutes.

How does CJC-1295 compare to Sermorelin?

Both peptides bind GHRHR on pituitary somatotrophs and activate adenylate cyclase, raising intracellular cAMP to trigger pulsatile GH release. Research shows the distinguishing feature of CJC-1295 (no DAC) is its four substitutions — Ala²→Aib, Gln⁸→Ala, Ala¹⁵→Aib, Leu²⁷→Nle — which block DPP-IV cleavage at the N-terminal dipeptide, the rapid-inactivation step for native GHRH (Jette et al., 2005, PMID: 16352683). The result is longer receptor activation per administration while still preserving pulsatile GH physiology. Sermorelin, by contrast, more closely mirrors the full endogenous GHRH structure but is cleared faster.

What does the evidence show?

Jette et al. (2005) documented dose-dependent GH elevation and a 6+ hour duration of GH effect for CJC-1295 (no DAC) in healthy adults (PMID: 16352683). Corpas et al. (1993) showed Sermorelin increased mean GH pulse amplitude and 24-hour integrated GH in older men. Both are studied as tools for GH-axis restoration research; CJC-1295 (no DAC) is often selected when longer receptor coverage per administration is the research variable of interest.

Because they share a receptor and pathway, the choice between them in research is driven by stability and duration, not by mechanism. See the CJC-1295 monograph and the Sermorelin monograph.

Research Use Only · Not for human consumption · Not for veterinary use.