CJC-1295 (no DAC) + Ipamorelin: Why Researchers Pair These Two Peptides

Growth hormone release from the anterior pituitary is governed by two distinct receptor systems. The GHRH receptor responds to GHRH and its analogues — CJC-1295 belongs here. The ghrelin receptor (GHSR-1a) responds to growth hormone secretagogues — ipamorelin belongs to this family. Activating both receptors simultaneously produces a synergistic effect on GH release that is greater than the simple additive sum of the two, a phenomenon well documented in classical endocrinology literature.

This is the pharmacologic rationale behind the CJC-1295 + Ipamorelin blend studied across research settings: pair one of each class to model a more complete, physiologic-like GH pulse.

CJC-1295 exists in two forms in the research literature. The variant with the Drug Affinity Complex (DAC) covalently binds to serum albumin, producing a half-life measured in days and a flattened, sustained increase in GH and IGF-1. The variant without DAC — sometimes called modified GRF(1-29) or simply CJC-1295 (no DAC) — preserves the four amino acid substitutions that protect against enzymatic degradation but lacks the albumin-binding maleimide moiety. The result is a peptide with a half-life of approximately 30 minutes, which preserves pulsatile rather than tonic GH release.

The original PK characterization of CJC-1295 by Teichman et al. in JCEM (2006) demonstrated dose-dependent and sustained increases in mean GH and IGF-1 in healthy adults using the DAC-conjugated form. CJC-1295 (no DAC) shares the same receptor target but is selected by researchers who want pulsatility preserved.

Ipamorelin was first described by Raun and colleagues at Novo Nordisk in 1998 as the first pentapeptide GH secretagogue with strong selectivity. Unlike earlier GH secretagogues such as GHRP-6 and GHRP-2 — which also drive substantial release of cortisol, prolactin, and ACTH — ipamorelin selectively stimulates GH release in preclinical models, with minimal effect on the HPA axis at standard study doses.

That selectivity profile is the reason ipamorelin is typically paired with CJC-1295 rather than its older GHRP cousins: researchers can isolate the effect of GH/IGF-1 pulsatility without the confounding signal of stress-axis activation.

When a GHRH analogue and a GH secretagogue are administered together, the resulting GH pulse can exceed the additive response of either compound alone — a synergy that has been characterized in classical human endocrinology studies dating back to the 1990s using native GHRH plus GHRP-6. The CJC-1295 (no DAC) + Ipamorelin blend recapitulates that pattern with two more selective, longer-lived modern peptides.

For research purposes, the combination is studied as a tool to perturb the GH/IGF-1 axis in ways that mimic endogenous pulsatility more closely than direct rhGH administration, which produces a continuous elevation that the body does not physiologically generate.

The blend is supplied lyophilized in a single vial, typically stored at -20°C, dry and protected from light. As with all GH-axis peptides, freeze-thaw cycles should be minimized and aggregation monitored.

This product is for in vitro and preclinical research use only. It is not intended or sold for human consumption. The research literature on combination GHRH/GHRP administration is largely characterized in healthy adult populations under clinical supervision; extrapolation outside those contexts is not supported.