CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH) that has attracted substantial interest in the peptide research community for its ability to engage GHRH receptors with notably extended binding kinetics. Unlike native GHRH(1–44), which is rapidly cleared by plasma dipeptidyl peptidase IV (DPP-IV), CJC-1295 incorporates strategic amino acid substitutions and, in its DAC-bearing form, a drug affinity complex technology that covalently binds circulating albumin — prolonging its half-life from minutes to days in preclinical models. This structural ingenuity has made CJC-1295 one of the most widely studied GHRH analogues in laboratory settings exploring pulsatile growth hormone (GH) secretion, IGF-1 axis signaling, and downstream metabolic biology.
Research into CJC-1295 spans two principal variants: CJC-1295 with DAC (drug affinity complex) and CJC-1295 without DAC (also referred to as Modified GRF(1–29) or Mod-GRF). Each variant presents a distinct pharmacokinetic profile of interest to investigators studying GH secretagogue biology, and understanding the mechanistic differences between them is essential for designing meaningful preclinical experiments. This guide consolidates available preclinical data, receptor biology, and structural chemistry to support researchers working with CJC-1295 in 2026.
Research-only notice: This content is provided for educational discussion and laboratory research purposes only. No medical claims are made or implied. CJC-1295 is a research compound not intended for human or animal use.
IGF-1 LR3 1MG — Research-Grade Reference Material IGF-1 LR3 1MG is supplied as a lyophilized powder for in-vitro laboratory research use only. SourcePeptides supplies this material strictly as a laboratory reference standard.…
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Kisspeptin - 10MG
$45.00$33.75 with 1st order
CJC 1295 No DAC (5MG) Ipamorelin (5MG) - 10MG
$75.00$56.25 with 1st order
CJC1295 w/ DAC - 5MG
$55.00$41.25 with 1st order
Semax - 10MG - Nasal Spray
$70.00$52.50 with 1st order
Frequently Asked Questions
What is CJC-1295 and how does it differ from native GHRH?
CJC-1295 is a synthetic 30-amino acid analogue of growth hormone-releasing hormone (GHRH). It differs from endogenous GHRH(1–44) through specific amino acid substitutions — most notably at positions 2, 8, 15, and 27 — that confer resistance to DPP-IV enzymatic cleavage, significantly extending its active half-life in preclinical models. The DAC variant additionally forms a covalent bond with circulating albumin, further prolonging receptor engagement compared to the No-DAC form.
What is the difference between CJC-1295 with DAC and CJC-1295 without DAC?
CJC-1295 with DAC incorporates a maleimido-propionic acid (MPA) linker — the Drug Affinity Complex — that enables covalent binding to endogenous albumin. Preclinical studies have reported a half-life of approximately 5–8 days for the DAC variant. CJC-1295 without DAC (Mod-GRF(1–29)) lacks this linker and exhibits a shorter half-life of approximately 30 minutes, producing a more acute, pulsatile GH release pattern in animal models.
How does CJC-1295 interact with the GHRH receptor?
CJC-1295 binds to the GHRH receptor (GHRHR), a class B G protein-coupled receptor expressed primarily on somatotroph cells in the anterior pituitary gland. Receptor binding activates adenylyl cyclase via Gs proteins, increasing intracellular cyclic AMP (cAMP) and triggering calcium-dependent exocytosis of GH-containing secretory granules. Preclinical data suggests CJC-1295 engages this pathway with high affinity and sustained duration compared to native GHRH.
What preclinical models have been used to study CJC-1295?
Published preclinical investigations have utilized rodent models (primarily rats and mice) and non-human primates to characterize CJC-1295’s pharmacokinetic and pharmacodynamic properties. Studies have examined GH pulse amplitude, IGF-1 serum concentrations, and downstream signaling cascades in these models. In vitro receptor binding assays have also been employed to characterize affinity at the GHRHR.
Is CJC-1295 often combined with other secretagogues in research?
Yes. Preclinical research has frequently co-administered CJC-1295 with ghrelin receptor agonists such as ipamorelin to investigate synergistic GH release via dual receptor stimulation. The CJC-1295 and ipamorelin combination targets complementary receptor pathways — GHRHR and the ghrelin receptor (GHSR-1a) respectively — and is a well-documented combination in the preclinical GH biology literature.
What does the IGF-1 axis have to do with CJC-1295 research?
GH secreted downstream of GHRHR activation stimulates hepatic production of insulin-like growth factor 1 (IGF-1). Preclinical studies of CJC-1295 commonly measure serum IGF-1 as a downstream biomarker of GHRHR engagement and sustained GH secretion. Elevated IGF-1 concentrations in animal models following CJC-1295 administration have been reported in multiple published studies, providing an indirect index of GHRH axis activation.
What is Mod-GRF(1–29) and how does it relate to CJC-1295?
Mod-GRF(1–29) is the common research synonym for CJC-1295 without DAC. It refers to the first 29 amino acids of GHRH, modified with four amino acid substitutions to resist DPP-IV enzymatic degradation. It lacks the albumin-binding maleimide linker found in the DAC variant, resulting in a shorter active window. Both compounds engage the GHRHR but exhibit distinct pharmacokinetic profiles in preclinical models.
GHRH Receptor Biology: The Molecular Foundation
To understand why CJC-1295 has become such a compelling research tool, it is essential to first appreciate the biology of the GHRH receptor system. The GHRHR is a class B (secretin family) G protein-coupled receptor expressed predominantly on somatotroph cells of the anterior pituitary. Upon ligand binding, the receptor couples to the stimulatory Gs alpha subunit, activating adenylyl cyclase and generating a surge of intracellular cAMP. This second-messenger cascade activates protein kinase A (PKA), which phosphorylates key transcription factors including cAMP response element-binding protein (CREB), ultimately driving both immediate GH exocytosis and longer-term GH gene transcription.
IGF-1 LR3 1MG — Research-Grade Reference Material IGF-1 LR3 1MG is supplied as a lyophilized powder for in-vitro laboratory research use only. SourcePeptides supplies this material strictly as a laboratory reference standard.…
View Research Data
Kisspeptin - 10MG
$45.00$33.75 with 1st order
CJC 1295 No DAC (5MG) Ipamorelin (5MG) - 10MG
$75.00$56.25 with 1st order
CJC1295 w/ DAC - 5MG
$55.00$41.25 with 1st order
Semax - 10MG - Nasal Spray
$70.00$52.50 with 1st order
Endogenous GHRH is secreted from the arcuate nucleus of the hypothalamus in a pulsatile manner, traveling through the hypothalamic-pituitary portal vasculature to reach somatotrophs. However, free GHRH in plasma is highly susceptible to cleavage at the His2-Ala3 bond by DPP-IV, rendering it biologically inactive within minutes. CJC-1295 overcomes this limitation through substitution of alanine at position 2 with D-alanine, along with modifications at positions 8, 15, and 27 that collectively confer enzymatic resistance without impairing receptor binding affinity.
Somatotroph Physiology and Pulsatility
A critical concept in GHRH research is GH pulsatility. Growth hormone is not secreted tonically — its release follows ultradian rhythms governed by the interplay of stimulatory GHRH and inhibitory somatostatin (SST). High-amplitude GH pulses, rather than continuous low-level secretion, appear to be essential for mediating many downstream biological effects, including robust IGF-1 production. CJC-1295 without DAC, by virtue of its shorter half-life, is hypothesized to preserve or amplify pulsatile GH dynamics more faithfully than the long-acting DAC variant, which tends to elevate GH more continuously in animal models. Researchers investigating GH pulse biology often choose between the two CJC-1295 forms based on whether pulsatile or sustained GH secretion profiles are of experimental interest.
Structural Chemistry: DAC Technology and Albumin Binding
The Drug Affinity Complex (DAC) system represents a significant biochemical innovation in peptide pharmacokinetics research. In CJC-1295 with DAC, a maleimido-propionic acid (MPA) group is conjugated to the lysine residue at position 29 via an amide bond. Once in the plasma, this reactive maleimide moiety undergoes a Michael addition reaction with the free thiol group of cysteine-34 on serum albumin — the most abundant plasma protein, which itself has a half-life of approximately 19 days in humans and 2–3 days in rodents.
By hijacking albumin’s long circulatory lifespan, CJC-1295 with DAC achieves plasma half-lives of approximately 5–8 days in preclinical rodent studies. This represents an increase of several orders of magnitude relative to native GHRH or even the No-DAC modified analogue. From a research design perspective, this prolonged activity window enables investigators to examine GH axis responses over extended observation periods without frequent re-administration, simplifying experimental protocols.
Comparative Structural Summary
| Feature | CJC-1295 with DAC | CJC-1295 No DAC (Mod-GRF) |
|---|---|---|
| Amino acid sequence | Modified GHRH(1–29) + DAC linker | Modified GHRH(1–29) |
| DPP-IV resistance | Yes | Yes |
| Albumin binding | Yes (covalent, via MPA) | No |
| Approximate half-life (preclinical) | 5–8 days | ~30 minutes |
| GH secretion pattern (observed) | Sustained / blunted pulse | Acute pulsatile amplification |
| IGF-1 elevation duration | Prolonged (days) | Hours |
| Primary research application | Long-term GH axis studies | Pulsatile GH dynamics studies |
CJC-1295 with DAC – 5MG Nasal Spray for research →
CJC-1295 No DAC / Ipamorelin – 10MG Nasal Spray for research →
Key Preclinical Study Findings
The foundational pharmacokinetic characterization of CJC-1295 was published by Jetté and colleagues in 2005 in the Journal of Clinical Endocrinology & Metabolism. This study examined GH and IGF-1 responses in healthy adult subjects and in animal models following CJC-1295 with DAC administration. In the animal component, dose-dependent increases in mean plasma GH concentrations were observed, with sustained IGF-1 elevations persisting for up to 14 days after a single administration in some models. These findings cemented CJC-1295’s reputation as a long-acting GHRH analogue of significant research interest.
GH Pulse Amplitude and Frequency
Subsequent rodent studies have explored how CJC-1295 No DAC alters GH pulse dynamics. In these models, administration of the No-DAC variant was associated with increased GH pulse amplitude without a corresponding significant change in pulse frequency, consistent with the known mechanism of GHRH action (which primarily amplifies pulse height rather than altering pulse timing). This preservation of pulsatile architecture is of interest to researchers studying the physiological versus pharmacological consequences of GHRH axis stimulation.
Synergy with Ghrelin Receptor Agonists
A well-replicated observation in the preclinical literature is the synergistic GH-releasing effect observed when GHRH analogues are co-administered with ghrelin receptor (GHSR-1a) agonists such as ipamorelin. Ipamorelin research has demonstrated that ghrelin-pathway activation not only stimulates GH release independently but also potentiates GHRH-driven secretion by sensitizing somatotrophs to GHRH. When CJC-1295 and ipamorelin are combined in rodent models, GH responses exceed what either compound produces individually — a finding that has made this pairing a frequently investigated combination in preclinical GH biology research.
IGF-1 Axis Downstream Effects
Multiple rodent studies have documented that sustained GHRHR engagement by CJC-1295 with DAC produces prolonged elevations in serum IGF-1, reflecting continuous hepatic GH signaling. The IGF-1 receptor (IGF-1R) is a receptor tyrosine kinase that mediates many of GH’s anabolic and metabolic downstream effects in tissue models. Researchers have used CJC-1295-driven IGF-1 elevation as an experimental platform for studying IGF-1R signaling cascades, including PI3K/Akt and MAPK/ERK pathways, in various tissue types. This makes CJC-1295 a versatile tool for investigating not just pituitary biology but also peripheral GH-IGF axis signaling.
IGF-1 LR3 – 1MG for research →
CJC-1295 in the Context of Broader GH Secretagogue Research
CJC-1295 does not operate in isolation within the GH biology research landscape. Understanding where it sits relative to other secretagogue classes is important for experimental design. The GH secretagogue family broadly includes GHRH analogues (of which CJC-1295 is the most studied), ghrelin mimetics (such as ipamorelin and GHRP-6), and somatostatin inhibitors. Each class engages distinct receptor populations and produces subtly different GH secretion profiles in preclinical models.
For researchers interested in the interplay between GH axis stimulation and broader metabolic peptide biology, it is also worth noting that GLP-class peptides studied in related metabolic research contexts — such as those documented in GLP-1 and GLP-2 comparative research — activate entirely separate receptor systems yet share overlapping research themes around metabolic signaling and tissue biology. Understanding these distinctions helps investigators design hypothesis-driven experiments that isolate the specific contribution of GHRH axis activity.
Combination Research: CJC-1295 + Ipamorelin
As noted above, the CJC-1295 / ipamorelin combination is one of the most consistently studied peptide pairings in the GH secretagogue literature. From a mechanistic standpoint, the rationale is straightforward: GHRH (via CJC-1295) maximally activates the Gs/cAMP pathway in somatotrophs, while ghrelin agonists (via ipamorelin) simultaneously suppress somatostatin tone and activate a distinct Gq-coupled calcium signaling pathway. The convergence of these two pro-secretory mechanisms produces synergistic GH release that neither compound achieves alone. Researchers designing studies of pituitary physiology, GH pulse dynamics, or IGF-1 axis responses frequently leverage this combination for its robust and reproducible preclinical pharmacology.
CJC-1295 No DAC / Ipamorelin – 20MG for research →
Ipamorelin – 10MG Nasal Spray for research →
Choosing Between CJC-1295 Variants for Research
Choose CJC-1295 with DAC if…
- The research objective requires sustained, multi-day GH axis stimulation without frequent re-administration
- The experimental model involves longitudinal tracking of IGF-1 as a downstream biomarker over days to weeks
- The investigator is studying chronic GHRHR engagement and potential receptor regulation or desensitization dynamics
- Simplified dosing protocols are required due to animal model constraints
Choose CJC-1295 No DAC if…
- The research question centers on pulsatile GH release physiology and the preservation of natural GH rhythm architecture
- Acute GH pulse amplitude studies are the primary endpoint
- The compound is being combined with ipamorelin or another GHSR agonist to investigate synergistic pulsatile GH dynamics
- Shorter experimental windows are planned and rapid clearance between sampling periods is desirable
Laboratory Handling and Reconstitution Considerations
For researchers preparing CJC-1295 for preclinical in vitro or in vivo model use, standard peptide handling practices apply. CJC-1295 is typically supplied as a lyophilized powder and requires reconstitution in an appropriate aqueous vehicle. As discussed in our guide on bacteriostatic water quality, the choice of reconstitution vehicle significantly affects peptide stability, sterility, and the reliability of preclinical results. Using research-grade bacteriostatic water minimizes the risk of microbial contamination during multi-use reconstitution protocols. Storage of lyophilized CJC-1295 at −20°C is standard practice, with reconstituted solutions typically held at 2–8°C and used within a defined timeframe according to laboratory SOPs.
The DAC variant warrants particular care during reconstitution, as the maleimide linker is reactive and may be sensitive to conditions that promote premature albumin binding or hydrolysis prior to in vivo use. Researchers are advised to consult published protocols and work under conditions that minimize oxidative stress to the compound.
Pfizer Hospira Bacteriostatic Water – 30 mL for research →
Where These Fit in Your Research Library
CJC-1295 occupies a central position in any GH secretagogue research library. Investigators building a comprehensive toolkit for pituitary biology and GH axis studies will find the following research compounds complementary:
- CJC-1295 No DAC / Ipamorelin – 20MG →
- CJC-1295 No DAC / Ipamorelin – 10MG Nasal Spray →
- IGF-1 LR3 – 1MG →
Explore the full research peptide catalog at SourcePeptides.co →
Final Takeaway: CJC-1295 as a GHRH Research Tool
CJC-1295 represents one of the most pharmacologically refined GHRH analogues available for preclinical research. Its two principal variants — the long-acting DAC form and the shorter-acting No-DAC (Mod-GRF) form — provide investigators with flexible tools for studying GHRH receptor biology across a range of experimental timescales and GH secretion models. The substantial preclinical literature documenting its IGF-1-elevating properties, synergy with ghrelin-pathway agonists, and well-characterized albumin-binding pharmacokinetics makes CJC-1295 an indispensable reference compound for researchers studying the hypothalamic-pituitary GH axis in 2026. Whether used alone or in combination with ipamorelin, CJC-1295 continues to generate meaningful preclinical insights into the fundamental biology of growth hormone secretion.
Sources & Further Reading
- Jetté L et al. — “hGRF1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog” — Endocrinology (2005)
- PubMed Search — GHRH receptor somatotroph biology — PubMed (Multiple Years)
- Tannenbaum GS, Bowers CY — “Interactions of growth hormone secretagogues and growth hormone-releasing hormone/somatostatin” — Endocrine (2001)
- Alba M et al. — “Once-daily administration of CJC-1295, a long-acting growth hormone-releasing hormone (GHRH) analog, normalizes growth in the GHRH knockout mouse” — American Journal of Physiology (2006)
- PubMed Search — Ipamorelin and GHRH synergy in growth hormone secretion — PubMed (Multiple Years)
