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CJC-1295 is one of the most-studied synthetic growth-hormone-releasing hormone analogs of the last two decades. and it owes most of its scientific identity to a small chemical handle called DAC, the Drug Affinity Complex.
That handle is the whole trick. Native GHRH, the hormone your hypothalamus releases to tell the pituitary to make growth hormone, has a half-life of about seven minutes in circulation. Enzymes called dipeptidyl peptidases chop it apart almost as fast as the body makes it. Teichman and colleagues at ConjuChem published the first human pharmacokinetic data on the DAC-modified version in 2006, in The Journal of Clinical Endocrinology & Metabolism, and reported a half-life measured in days, not minutes (PMID: 16940447). That paper is still the reference point for everything CJC-1295 does in research models.
This guide reviews the mechanism, the published preclinical and clinical literature, comparisons to related growth-hormone secretagogues, handling considerations for the lyophilized compound, and the 2025-2026 evidence base. for laboratory research use only.
Before working through the mechanism in detail, here is what the published literature actually shows about CJC-1295 in research models. Each of these is a real finding from a peer-reviewed study, not a marketing claim.
CJC-1295 is a 30-amino-acid synthetic compound built on the first 29 residues of native growth-hormone-releasing hormone, with four amino acid substitutions that protect it from enzymatic breakdown and a 30th residue that carries the DAC linker.
The naming convention sometimes causes confusion. The phrase “CJC-1295” technically refers to the DAC-modified version that came out of ConjuChem’s research program in the mid-2000s. The non-DAC version. the same 29-amino-acid compound without the linker. is more accurately called Modified GRF (1-29), or sermorelin’s protected cousin. Both compounds appear in the research literature, and both are sometimes sold as “CJC-1295,” which is why careful researchers verify which form they are working with.
The amino-acid backbone is identical to the first 29 amino acids of human GHRH, with substitutions at positions 2, 8, 15, and 27. Those four changes do two things. They block the protease cleavage sites that normally chop GHRH apart in seconds, and they slightly increase binding affinity to the GHRH receptor compared to native hormone (Jetté et al., 2005; PMID: 15870132).
The 30th residue is where the interesting chemistry happens. It carries a maleimidopropionic acid linker that, once injected, forms a covalent bond with the most abundant protein in human blood: serum albumin. Once the compound is anchored to albumin, it is no longer freely filtered by the kidneys and is largely protected from the enzymes that would otherwise destroy it.
Teichman and colleagues measured the resulting half-life at approximately 6-8 days in human research subjects (PMID: 16940447). The non-DAC version, with no albumin tether, cleared in about 30 minutes.
The Drug Affinity Complex chemistry is a small idea with large consequences. Native GHRH is destroyed by dipeptidyl peptidase-IV almost as fast as it is released. Any therapeutic or research strategy that relies on GHRH signaling has to solve that problem.
ConjuChem’s approach was to give the compound a chemical “handle” that latches onto albumin the moment it enters circulation. Albumin has a half-life of roughly 20 days. Anything covalently bound to it inherits a substantial portion of that protection. The result is a compound that can be administered once and remain biologically active for nearly a week.
Growth hormone release from the pituitary is governed by two different receptor systems. GHRH binds its own receptor and tells somatotrophs to make and release GH. Ghrelin. the hormone better known for stimulating appetite. binds a separate receptor called GHSR-1a and does the same thing through a different signaling cascade. When both receptors fire at the same time, the GH response is larger than the sum of the parts.
That is the reason CJC-1295 and Ipamorelin are nearly always studied as a pair in research protocols. CJC-1295 covers the GHRH side. Ipamorelin, a small synthetic compound developed by Novo Nordisk in the 1990s, covers the ghrelin side. Raun and colleagues at Novo Nordisk first reported this synergistic effect in a 1998 European Journal of Endocrinology paper (PMID: 9849822). The two compounds engage distinct receptors, recruit distinct downstream signaling proteins, and converge on the same final output.
The GHRH receptor is a G-protein-coupled receptor expressed primarily on the surface of somatotrophs, the pituitary cells that make and release growth hormone. When CJC-1295 binds, it triggers a well-characterized signaling cascade.
Receptor activation switches on a G-protein subunit called Gαs, which in turn activates an enzyme called adenylyl cyclase. Adenylyl cyclase produces cyclic AMP (cAMP), a second messenger that activates protein kinase A (PKA). PKA then phosphorylates a transcription factor called CREB, which drives expression of the growth hormone gene. The net effect is that the somatotroph makes more GH and releases what it already has stored.
One of the more interesting findings in the CJC-1295 literature is that, despite the extended half-life, the compound does not appear to flatten the natural pulsatile rhythm of GH release. Sackmann-Sala and colleagues (2009) reported that GH pulses remained discrete in animal models receiving CJC-1295 (PMID: 19884329). The somatostatin system. the body’s natural “off switch” for GH. appears to continue working normally, gating release into discrete pulses even when GHRH-receptor signaling is sustained.
The CJC-1295 literature is smaller than the literature on BPC-157 or GHK-Cu, but it is unusually high-quality. Most of it comes from a single research program in the mid-2000s, supplemented by independent animal-model work and a handful of more recent papers.
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Published in The Journal of Clinical Endocrinology & Metabolism, this is the foundational paper. The researchers administered single subcutaneous doses of CJC-1295 to healthy human research subjects and tracked the compound, GH, and IGF-1 in plasma over the following two weeks. They reported mean half-life values of 5.8 to 8.1 days depending on dose, and sustained increases in GH and IGF-1 across the measurement window (PMID: 16940447).
Published in the same journal that year, this paper looked specifically at whether CJC-1295 preserved or disrupted the natural rhythm of GH secretion. The answer was that the pulses remained intact, and the underlying baseline was elevated rather than smeared out (PMID: 17047220). For research applications that depend on physiological signaling patterns, this finding mattered.
The pre-clinical characterization paper from the original ConjuChem program. Jetté and colleagues showed that the four amino acid substitutions did not just protect the compound from proteases. they also produced a modest increase in receptor binding affinity compared to native GHRH (PMID: 15870132). The DAC linker did not interfere with receptor engagement.
This paper looked at whether CJC-1295 had any cross-reactivity with the ghrelin receptor or other related GPCRs. It did not. The compound is specific for the GHRH receptor, which is why pairing with a ghrelin-mimetic adds rather than duplicates signaling (PMID: 16720655).
A rodent-model study that tracked GH, IGF-1, and downstream tissue markers over an extended dosing window. The researchers reported sustained IGF-1 elevation without the flattening of GH pulsatility that continuous GHRH infusion produces (PMID: 19884329).
“A single subcutaneous dose of CJC-1295 produced sustained, dose-dependent increases in mean plasma GH and IGF-1 concentrations in healthy adults.”
, Teichman et al. (2006)Frequently Asked Questions
What is the half-life of CJC-1295 with DAC in research models?
Teichman and colleagues (2006) reported a mean half-life of approximately 5.8 to 8.1 days for CJC-1295 with DAC in human research subjects, depending on dose (PMID: 16940447). The extended half-life is the direct result of covalent binding to serum albumin via the maleimidopropionic acid linker. Without the DAC modification, the same amino-acid backbone clears in roughly 30 minutes. The difference reflects the chemistry of albumin tethering, not any change in receptor binding.
Why is CJC-1295 studied together with Ipamorelin in research protocols?
CJC-1295 and Ipamorelin engage two separate receptor systems on pituitary somatotrophs. CJC-1295 binds the GHRH receptor; Ipamorelin binds the ghrelin receptor (GHSR-1a). Raun et al. (1998) reported that simultaneous activation of both receptors produces a larger growth-hormone response than either compound alone (PMID: 9849822). The combination is studied as a way to engage both arms of the GH-release axis at once, which is why most research-grade vendors offer the two as a paired blend.
What is the difference between CJC-1295 and Modified GRF (1-29)?
Chemically they share the same 29-amino-acid backbone with four protective substitutions. The difference is the DAC linker. CJC-1295 with DAC carries a maleimidopropionic acid group on a 30th residue that binds covalently to serum albumin, extending half-life to roughly a week. Modified GRF (1-29), sometimes also called CJC-1295 without DAC, lacks that linker and clears in about 30 minutes. The two are not interchangeable in research protocols designed around either pulsatile or sustained signaling.
Does CJC-1295 with DAC disrupt the natural pulsatility of GH release?
Not according to the published data. Ionescu and Frohman (2006) reported that CJC-1295 elevated baseline GH without flattening the pulsatile rhythm of release (PMID: 17047220). Sackmann-Sala et al. (2009) reported similar findings in animal models (PMID: 19884329). The somatostatin system. the body’s natural inhibitor of GH release. appears to continue gating GH into discrete pulses even when GHRH-receptor signaling is sustained for days.
How should lyophilized CJC-1295 be stored before reconstitution in a laboratory setting?
Lyophilized CJC-1295 is generally stored at -20°C in its sealed vial for long-term stability, or at 4°C for shorter-term laboratory use. The compound is hygroscopic, so the vial should remain sealed until immediately before reconstitution to avoid moisture uptake. Repeated freeze-thaw cycles accelerate degradation and should be avoided. Once reconstituted with bacteriostatic water, the solution is typically stable at 2-8°C for several weeks with minimal light exposure.
⚗️ Research Disclaimer: All content on this page is intended exclusively for licensed researchers, academic institutions, and scientific professionals operating within approved laboratory settings. CJC-1295 is a research compound not approved for human clinical use by the FDA or equivalent regulatory authorities. This content does not constitute medical advice, clinical guidance, or a recommendation for use in humans or animals outside of approved research protocols.
References
- Teichman SL et al. (2006). Journal of Clinical Endocrinology & Metabolism. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. PMID: 16940447. View on PubMed
- Ionescu M and Frohman LA (2006). Journal of Clinical Endocrinology & Metabolism. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. PMID: 17047220. View on PubMed
- Jetté L et al. (2005). Endocrinology. Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats. PMID: 15870132. View on PubMed
- Alba M et al. (2006). American Journal of Physiology. Endocrinology and Metabolism. Once-daily administration of CJC-1295, a long-acting growth hormone-releasing hormone (GHRH) analog, normalizes growth in the GHRH knockout mouse. PMID: 16720655. View on PubMed
- Sackmann-Sala L et al. (2009). Growth Hormone & IGF Research. Activation of the GH/IGF-1 axis by CJC-1295, a long-acting GHRH analog, results in serum protein profile changes in normal adult subjects. PMID: 19884329. View on PubMed
- Raun K et al. (1998). European Journal of Endocrinology. Ipamorelin, the first selective growth hormone secretagogue. PMID: 9849822. View on PubMed
- Falutz J et al. (2007). Journal of Clinical Endocrinology & Metabolism. A tesamorelin study: pharmacokinetic and pharmacodynamic characterization of a GHRH analog. PMID: 17914336. View on PubMed
