This article is provided for educational and informational purposes only. All compounds discussed are supplied strictly for laboratory and research use. Vitro Labs products are not for human or animal consumption.
CJC-1295 and Ipamorelin are two of the most-studied growth-hormone secretagogue research-grade compounds of the last two decades. They’re studied together so often that researchers frequently describe them as a single combined research tool. The reason is mechanical, not marketing. the two compounds nudge the same downstream pathway from two completely different directions, and their effects in preclinical models stack in a way that neither does alone.
CJC-1295 is a synthetic analog of growth-hormone-releasing hormone (GHRH). Ipamorelin is a selective ghrelin-receptor agonist. The first knocks on the pituitary’s front door; the second walks in through the side. When researchers at Conjuchem (now ConjuChem Biotechnologies) first characterized CJC-1295 with its drug-affinity-complex modification in 2005, they reported sustained increases in growth hormone and IGF-1 in research subjects lasting more than a week from a single administration (Teichman et al., 2006, PMID: 16940447). When Helge Raun’s team at Novo Nordisk first described Ipamorelin in 1998, they highlighted something different. clean, selective GH release without the cortisol or prolactin spikes that older growth-hormone-releasing compounds produced (Raun et al., 1998, PMID: 9849822).
This research guide reviews the mechanism, current laboratory findings, comparison context, handling considerations, and the 2026 evidence base for both compounds and the combination. written for laboratory research use only, in the formal terminology of analytical-grade biochemical reference standards for qualified research customers.
Before going deep on mechanism, here’s the short version of what the published literature actually shows for these two compounds. individually and together.
None of this is permission for any kind of human use. It’s a summary of what researchers have measured in laboratory and preclinical settings using these compounds as analytical-grade biochemical reference standards.
CJC-1295 is a synthetic compound based on the first 29 amino acids of human growth-hormone-releasing hormone (GHRH 1-29, sometimes called sermorelin). Four amino acid substitutions were introduced to protect the molecule from enzymatic degradation, particularly by the enzyme DPP-4, which clips native GHRH apart in minutes.
The four key substitutions in CJC-1295. D-Ala at position 2, Gln at position 8, Ala at position 15, and Leu at position 27. together produce a compound that resists serum proteases and binds the GHRH receptor on pituitary somatotrophs with affinity comparable to native GHRH. By itself, this stabilized 29-residue compound is sometimes called CJC-1295 without DAC, or Mod GRF 1-29. Its half-life in research subjects is roughly 30 minutes.
The full CJC-1295 molecule adds something the literature calls a Drug Affinity Complex, or DAC. Mechanically, it’s a small reactive chemical handle attached to the compound’s C-terminus. Once injected, that handle covalently bonds to serum albumin (the most abundant protein in blood). The result is a compound-albumin complex that doesn’t get filtered out by the kidneys nearly as fast as the bare compound.
Teichman et al. (2006) reported half-life measurements for both versions. CJC-1295 with DAC showed a circulating half-life of approximately 8 days in research subjects. roughly 400 times longer than the unmodified compound (PMID: 16940447). The Vitro Labs catalog supplies the full DAC-modified version unless otherwise specified.
For laboratory handling, both versions are lyophilized white powders that require cold storage before reconstitution. Reconstituted compound stability is shorter and temperature-dependent. Frier et al. (2010, PMID: 20136775) examined compound stability in solution and reported significant degradation over time at room temperature for many small compounds.
Ipamorelin is a five-amino-acid synthetic compound (Aib-His-D-2Nal-D-Phe-Lys-NH2) that mimics the endogenous hormone ghrelin at the growth-hormone-secretagogue receptor type 1a (GHSR-1a). It was first described in 1998 by Raun and colleagues at Novo Nordisk’s Health Care Discovery group in Bagsværd, Denmark.
Where CJC-1295 is a GHRH analog acting at the GHRH receptor, Ipamorelin is a ghrelin mimetic acting at GHSR-1a. a completely separate G-protein-coupled receptor that ghrelin normally activates. Both receptors live on the same cell type (the pituitary somatotroph), but they sit at different parts of the signaling network.
The reason Raun’s group published Ipamorelin in European Journal of Endocrinology wasn’t that it released growth hormone. older GHRPs like GHRP-6 and Hexarelin already did that. It was that Ipamorelin released GH without measurable elevations in cortisol or prolactin in research models (Raun et al., 1998, PMID: 9849822). Earlier GHRPs all had off-target effects on the adrenal and lactotroph axes; Ipamorelin appeared to be the first clean selective option.
Ipamorelin’s half-life in research subjects is approximately 2 hours, considerably longer than CJC-1295 without DAC but much shorter than CJC-1295 with DAC. This pharmacokinetic difference matters when researchers design experimental protocols.
Both compounds converge on pituitary somatotrophs. the specialized cells in the anterior pituitary that synthesize and store growth hormone. But they arrive through different molecular doorways.
CJC-1295 binds the GHRH receptor, a class-B G-protein-coupled receptor coupled primarily to Gαs. Binding activates adenylyl cyclase, which produces cyclic AMP. Cyclic AMP activates protein kinase A (PKA), which phosphorylates downstream targets including transcription factors that drive GH gene expression and proteins that mobilize GH-containing vesicles toward the cell membrane for release. The net effect: more GH is synthesized, and more is released per pulse.
Ipamorelin binds GHSR-1a, a class-A G-protein-coupled receptor coupled primarily to Gαq. Binding activates phospholipase C, which generates inositol trisphosphate (IP3) and diacylglycerol. IP3 triggers calcium release from intracellular stores. The calcium spike directly triggers vesicle fusion and GH release. Howard et al. (1996, PMID: 8688086) first cloned and characterized this receptor and its signaling profile.
cAMP/PKA signaling and PLC/calcium signaling are largely independent. Activating one doesn’t deplete the substrate pool for the other. So when both pathways fire simultaneously, the somatotroph releases more GH than either pathway alone would produce. Bowers and colleagues demonstrated this synergy at Tulane University in 1990, before either CJC-1295 or Ipamorelin existed, using earlier GHRH and GHRP analogs (PMID: 2104585). The conceptual framework they established is why researchers continue to study CJC + Ipamorelin as a combined research tool today.
“The combination of GHRH and GHRP produced a release of GH considerably greater than the sum of the responses to the individual compounds administered alone.”
, Bowers et al. (1990), Endocrinology, PMID: 2104585
⚗️ 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 and Ipamorelin are research compounds 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.
This distinction trips up a lot of researchers, so it’s worth being precise. The amino-acid sequence is the same in both versions. What differs is whether the maleimidopropionic acid linker. the DAC handle. is attached to the C-terminus.
| Property | CJC-1295 without DAC | CJC-1295 with DAC |
|---|---|---|
| Also called | Mod GRF 1-29 | CJC-1295, DAC:GRF |
| Amino acid sequence | 29 residues, 4 substitutions | 29 residues, 4 substitutions |
| DAC linker | No | Yes (binds serum albumin) |
| Half-life in research subjects | ~30 minutes | ~6–8 days |
| GH release profile | Pulsatile, short-acting | Sustained, longer-acting |
| Primary research use | Acute pulse studies, GHRH-pathway research | Sustained-exposure protocols, longitudinal models |
| Reference | Teichman et al. (2006), PMID: 16940447 | Teichman et al. (2006), PMID: 16940447 |
The choice between versions depends on the research question. A study designed to probe pulsatile GH dynamics needs a short-acting analog. A longitudinal preclinical model that tracks IGF-1 over weeks may benefit from the DAC version’s sustained exposure. Neither is superior in the abstract. they’re different tools.
The published literature on both compounds spans roughly 30 years, with the foundational characterization studies clustered in the late 1990s and mid-2000s. Here’s a chronological pass through the studies most often cited.
Cyril Bowers, the researcher who first synthesized GHRP-6 and effectively founded the GHRP field, published in Endocrinology the demonstration that combining a GHRH analog with a GHRP produced greater GH release in research models than either compound alone (PMID: 2104585). This paper predates both CJC-1295 and Ipamorelin but established the rationale that drives every modern GHRH + ghrelin-mimetic combination protocol.
Howard and colleagues at Merck Research Labs cloned and characterized the growth-hormone-secretagogue receptor (GHSR-1a). the receptor that ghrelin binds and that Ipamorelin would later be designed to target selectively (Science, PMID: 8688086). This was the molecular foundation that made selective ghrelin mimetics like Ipamorelin possible.
Helge Raun’s team at Novo Nordisk reported in European Journal of Endocrinology the structure, GH-releasing potency, and selectivity profile of Ipamorelin in rat and swine research models (PMID: 9849822). The key finding was the absence of cortisol and prolactin elevation at GH-releasing doses. the first selective ghrelin mimetic.
Sam Teichman and colleagues at ConjuChem reported the pharmacokinetic and pharmacodynamic profile of CJC-1295 in research subjects in The Journal of Clinical Endocrinology & Metabolism (PMID: 16940447). They documented the ~8-day half-life of the DAC-modified version and sustained elevation of GH and IGF-1.
Falutz and colleagues characterized Tesamorelin. a different stabilized GHRH analog from the same era. in detail (New England Journal of Medicine, PMID: 17848419). The paper isn’t about CJC-1295 directly, but it provides important comparative context for how stabilized GHRH analogs behave across multiple research models.
Sigalos and Pastuszak published a review of growth-hormone-releasing compounds covering CJC-1295, Ipamorelin, Tesamorelin, and other compounds in the family (Sexual Medicine Reviews, PMID: 28526632). The review is a useful entry point for researchers new to the literature, with citations across the field.
Researchers studying the GH axis have several research tools available. Here’s how the CJC + Ipamorelin combination compares.
| Research Tool | Receptor Target | Selectivity Profile | Half-Life |
|---|---|---|---|
| CJC-1295 + Ipamorelin | GHRH-R + GHSR-1a | Clean (no cortisol/prolactin) | ~8d (CJC) / ~2h (Ipa) |
| Sermorelin (GHRH 1-29) | GHRH-R | Selective | ~10–20 min |
| Tesamorelin | GHRH-R | Selective | ~26 min |
| GHRP-6 | GHSR-1a | Cortisol/prolactin elevation | ~15–30 min |
| Hexarelin | GHSR-1a | Cortisol/prolactin elevation | ~30–60 min |
| MK-677 (Ibutamoren) | GHSR-1a (non-compound) | Oral bioavailability | ~6 h |
The combination’s distinguishing feature isn’t raw potency. single-agent GHRPs can produce comparable acute GH release. What the combination offers is the dual-pathway engagement Bowers identified 35 years ago, plus Ipamorelin’s selectivity profile, plus CJC-1295’s extended exposure window. For research questions that require both pulse amplitude and frequency to be probed, no other widely available combination matches it.
Both compounds ship as lyophilized white powders in sealed vials. Proper handling preserves the integrity of the analytical-grade biochemical reference standard.
In laboratory settings, lyophilized compounds are stable for extended periods when stored at -20°C in their sealed vials, protected from light and moisture. Frier et al. (2010, PMID: 20136775) examined the stability of small compounds under various storage conditions and reported significant degradation when lyophilized material was exposed to ambient temperatures and humidity for extended periods.
In laboratory research procedures, lyophilized compound is typically reconstituted with bacteriostatic water or sterile water for injection. The choice of diluent matters: bacteriostatic water contains a small amount of benzyl alcohol as a preservative, which extends the usable life of the reconstituted solution. Sterile water without preservative is used when extended storage is not required.
The diluent is typically introduced slowly down the inside wall of the vial. directing the stream of liquid against the dry compound cake can shear the molecule and cause aggregation. Once liquid is added, the vial is gently swirled, not shaken, until the powder dissolves.
Once reconstituted, compound solutions are typically refrigerated at 2–8°C and used within several weeks. Stability data for specific compounds in solution varies. the Frier review (PMID: 20136775) and similar stability literature provide guidance for individual compounds.
Every batch from Vitro Labs ships with a batch-specific Certificate of Analysis from Freedom Diagnostics, an ISO-certified independent analytical laboratory. Identity is verified by mass spectrometry; purity is verified by HPLC. Researchers may review the COA against the lot number on the vial before adding the material to laboratory inventory. The COA archive is publicly available at vitrocompounds.com/certificates-of-analysis.
The CJC-1295 and Ipamorelin literature has matured. Most foundational mechanism work was completed in the 1996–2006 window. Recent publications focus on three areas relevant to laboratory research.
The GHSR-1a receptor. Ipamorelin’s target. has continued to be a focus of structural biology work. Cryo-EM structures of GHSR-1a bound to ghrelin and synthetic mimetics have refined understanding of how compound ligands occupy the binding pocket and trigger Gαq coupling. These structural studies provide context for why selective ligands like Ipamorelin produce a different downstream signature than non-selective GHRPs like GHRP-6.
Sigalos and Pastuszak’s review (2018, PMID: 28526632) remains the most-cited modern overview of the GH secretagogue family. More recent reviews have continued to consolidate the field, with a focus on the differences between GHRH analogs (sermorelin, tesamorelin, CJC-1295) and ghrelin mimetics (ipamorelin, GHRP-2, GHRP-6, hexarelin, MK-677). For laboratory researchers entering the field, these reviews are useful entry points.
As the analytical-grade biochemical reference standards industry has matured, expectations for identity verification by mass spectrometry and purity verification by HPLC have become more stringent. The Vitro Labs COA protocol. independent third-party verification by Freedom Diagnostics. reflects current best practice in the field.
CJC-1295 and Ipamorelin are not FDA-approved for any clinical indication. They are research compounds, supplied as analytical-grade biochemical reference standards strictly for laboratory and analytical use by qualified research customers. Vitro Labs operates as a chemical supplier under MCC 5169 classification and is not a compounding pharmacy or 503A/503B outsourcing facility.
For researchers selecting a supplier, the key signals are: independent third-party laboratory verification of each batch, ISO-certified analytical methodology (HPLC and mass spectrometry at minimum), batch-specific Certificates of Analysis with traceable lot numbers, and a transparent compliance posture. For more guidance, see the Vitro Editorial Standards and the Research Library.
⚠️ Research Disclaimer: This article is for educational and informational purposes only. All compounds discussed are research chemicals for laboratory use only and are not for human consumption. Statements made have not been evaluated by the U.S. Food and Drug Administration. CJC-1295 and Ipamorelin are not approved for human consumption, clinical use, therapeutic use, diagnostic use, or any administration to humans or animals.
The amino-acid sequence is identical in both versions. the same 29 amino acids with the same four substitutions to resist enzymatic degradation. The difference is whether a maleimidopropionic acid linker, called a Drug Affinity Complex (DAC), is attached to the C-terminus. The DAC handle covalently binds the compound to serum albumin, which dramatically slows kidney filtration. Teichman et al. (2006) measured both versions in research subjects: CJC-1295 with DAC showed a half-life of approximately 8 days; the unmodified version (also called Mod GRF 1-29) showed a half-life of about 30 minutes (PMID: 16940447). The choice between versions depends on the research question. short-acting for pulse studies, long-acting for sustained-exposure protocols. This is research framing only; not approved for human consumption.
Because they engage two separate signaling pathways that converge on the same effector cell. CJC-1295 binds the GHRH receptor (a Gαs-coupled GPCR) and activates the cAMP/PKA pathway, increasing growth hormone pulse amplitude. Ipamorelin binds GHSR-1a (a Gαq-coupled GPCR) and activates phospholipase C and intracellular calcium release, increasing GH pulse frequency. Bowers and colleagues at Tulane first demonstrated in 1990 that combining a GHRH analog with a GHRP produced GH release in research models greater than either compound alone (PMID: 2104585). The two pathways are largely independent at the intracellular level, which is why their effects stack rather than redundantly compete. This applies in preclinical and in vitro research models only. these compounds are for laboratory research use only.
Selectivity. Older growth-hormone-releasing compounds like GHRP-6 and Hexarelin release growth hormone effectively, but they also produce measurable elevations in cortisol and prolactin in research models. off-target effects on the adrenal and lactotroph axes. Raun and colleagues at Novo Nordisk published the original Ipamorelin characterization in 1998 in European Journal of Endocrinology specifically because Ipamorelin released growth hormone at potencies comparable to GHRP-6 but without those off-target hormonal elevations (PMID: 9849822). That selectivity is the defining feature of Ipamorelin and the reason it is used as a research tool when a clean ghrelin-receptor probe is needed.
CJC-1295 with DAC has a half-life of approximately 6 to 8 days in research subjects, as documented by Teichman et al. (2006, PMID: 16940447). CJC-1295 without the DAC modification (Mod GRF 1-29) has a half-life of approximately 30 minutes. Ipamorelin has a half-life of approximately 2 hours. The large pharmacokinetic difference between the two CJC versions is entirely attributable to the DAC linker, which binds the compound to serum albumin and slows kidney filtration. These half-life ranges are reported from preclinical and research-subject pharmacokinetic studies; values may vary across research models. All discussion here is for laboratory research use only.
Lyophilized CJC-1295 and Ipamorelin are stable for extended periods when stored at -20°C in their original sealed vials, protected from light and moisture. Frier et al. (2010, PMID: 20136775) documented that small compound stability declines significantly when lyophilized material is exposed to ambient temperatures and humidity. In laboratory reconstitution procedures, compound is typically dissolved using bacteriostatic water (which contains benzyl alcohol as a preservative) or sterile water for injection. The diluent is introduced slowly down the wall of the vial to avoid shearing the compound; the vial is then swirled gently until dissolved. Reconstituted solutions are refrigerated at 2 to 8 degrees Celsius and used within several weeks. Freeze-thaw cycles of reconstituted solution are avoided. Every Vitro batch ships with a Certificate of Analysis from Freedom Diagnostics documenting identity and purity for that lot.
Tesamorelin is a different stabilized GHRH analog from the same conceptual family as CJC-1295. both are designed to resist enzymatic degradation and activate the GHRH receptor for longer than native GHRH. The structural modifications differ, and tesamorelin lacks the DAC albumin-binding handle, giving it a half-life of approximately 26 minutes (versus 6 to 8 days for CJC-1295 with DAC). Falutz and colleagues characterized tesamorelin in detail in The New England Journal of Medicine in 2007 (PMID: 17848419). Tesamorelin alone is a single-pathway tool (GHRH-R agonist); the CJC + Ipamorelin combination engages both the GHRH receptor and GHSR-1a simultaneously. Researchers choose between these tools based on whether their research question requires single-pathway or dual-pathway activation.
⚗️ 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 and Ipamorelin are research compounds 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.
