CJC-1295 and Ipamorelin are two of the most frequently paired peptides in growth-hormone research — not because either is dramatic on its own, but because they stimulate the same output, growth-hormone (GH) release, through two different receptors. One imitates the body's growth-hormone-releasing hormone; the other imitates ghrelin. This guide summarizes what the peer-reviewed literature reports about each peptide, why they are studied together, and what the frequently seen "no DAC" label actually means — while being clear about where the human evidence is still thin.
CJC-1295 is a synthetic analog of growth-hormone-releasing hormone (GHRH), the hypothalamic signal that instructs the pituitary gland to secrete GH. It is built on the biologically active fragment of GHRH (residues 1–29, sometimes called GRF 1-29) with amino-acid substitutions that make the molecule more resistant to rapid enzymatic breakdown. In model systems it binds the GHRH receptor on pituitary somatotroph cells, prompting them to release stored growth hormone.
A published human study of the long-acting, albumin-binding form of CJC-1295 reported dose-dependent increases in mean plasma GH and in insulin-like growth factor I (IGF-I), illustrating that a stabilized GHRH analog can extend GHRH-type signaling well beyond that of the native hormone, whose therapeutic use is limited by its very short duration of action.
This is the detail most often misunderstood, so it is worth stating precisely. DAC stands for Drug Affinity Complex: a chemical group that binds CJC-1295 covalently to a single site (cysteine-34) on serum albumin, a long-lived carrier protein in blood. That tether dramatically slows clearance — the human study above estimated a half-life of roughly 5.8 to 8.1 days for the DAC form, with IGF-I elevated for many days after a single administration.
"No DAC" CJC-1295 — the form referenced by the catalog name and often called Modified GRF (1-29) — omits that albumin-binding complex. Without it, the peptide is cleared far more quickly and produces a shorter, more pulse-like pattern of GH signaling in the models studied, rather than a sustained, days-long elevation. Researchers who want to study GH release that more closely resembles the body's natural pulsatile rhythm tend to favor the "no DAC" version; this is the reason the combination product is specified as no DAC.
Ipamorelin approaches GH release from an entirely different direction. It is a growth-hormone secretagogue that mimics ghrelin, the "hunger hormone," at the growth-hormone secretagogue receptor (GHS-R) on the pituitary. In the study that introduced it, ipamorelin was described as "the first selective growth hormone secretagogue" — potent at releasing GH, yet notably clean in its side profile.
That selectivity is its defining feature in the literature. In the original characterization, ipamorelin released GH with a selectivity comparable to GHRH and, importantly, did not meaningfully raise ACTH or cortisol even at doses far above those needed for GH release, and showed no significant effect on prolactin, FSH, LH or TSH in the animal models tested. Earlier GH-releasing peptides such as GHRP-6 and GHRP-2 lacked this clean profile, which is why ipamorelin was flagged as an especially interesting research candidate.
The pairing follows directly from the biology. GH secretion is controlled by more than one upstream signal, and the GHRH pathway (engaged by CJC-1295) and the ghrelin/GHS-R pathway (engaged by Ipamorelin) are distinct and complementary. The research question that motivates the combination is whether activating both receptor systems at once yields a larger or more physiological GH pulse than activating either alone — a GHRH analog to raise the underlying signal, and a selective secretagogue to sharpen the pulse, without the off-target hormone release seen with older compounds.
It is essential to read any such "complementary" or "synergy" language as a description of observed activity in laboratory and preclinical models, not as a demonstrated human clinical outcome. The mechanistic rationale is well defined; the confirmation of combined human benefit is not.
The mechanistic and preclinical foundation for each peptide individually is well established. Ipamorelin's receptor selectivity was characterized in a peer-reviewed endocrinology study, and CJC-1295's ability to prolong GHRH-type signaling was documented in a published human pharmacology study of its long-acting form. In other words, the basic pharmacology of "how each one acts" is genuinely supported.
What remains limited is rigorous human data on the combination, and on many of the broad outcomes attributed to it in popular writing. Neither compound is an approved drug; much of what circulates as "results" for the pair is extrapolated from single-agent studies, animal models, or anecdote rather than large, controlled clinical trials of CJC-1295 with Ipamorelin together. Treating that preclinical and mechanistic work as proven human benefit is precisely the error this field is prone to, and we will not make it here.
For research applications, identity and purity are what separate a usable reference compound from an unknown. The blended peptide we supply to the research community is a lyophilized powder tested by HPLC, with a third-party Certificate of Analysis (COA) available for each lot, strictly for in-vitro laboratory use:
New to handling lyophilized peptides? See our Research Center for storage, reconstitution and COA guidance.
They act on two different pathways that both converge on growth-hormone release. CJC-1295 is an analog of growth-hormone-releasing hormone (GHRH) that signals through the GHRH receptor on pituitary somatotrophs. Ipamorelin is a selective growth-hormone secretagogue that mimics ghrelin at the growth-hormone secretagogue receptor (GHS-R). Because they engage complementary mechanisms, they are frequently studied as a pair in preclinical research.
DAC stands for Drug Affinity Complex, a chemical modification that binds CJC-1295 covalently to serum albumin and greatly extends its half-life — reported in a human study at roughly 5.8 to 8.1 days. "No DAC" CJC-1295 omits that modification, so it is cleared much faster and produces a shorter, more pulse-like pattern of growth-hormone release in the models studied. "No DAC" CJC-1295 is often referred to as Modified GRF (1-29).
Growth-hormone release is governed by more than one input. GHRH-type signaling (CJC-1295) and ghrelin-receptor signaling (Ipamorelin) act through separate receptors, and the research interest lies in whether stimulating both pathways at once produces a larger or more physiological growth-hormone pulse than either alone. Any such combined effect described in the literature comes from laboratory and preclinical models, not from established human clinical outcomes.
No. Neither CJC-1295 nor Ipamorelin is approved by the FDA as a drug. They are research compounds supplied strictly for in-vitro laboratory and analytical use, are not for human or animal consumption, and much of the available evidence comes from preclinical models rather than large controlled human trials.