CJC-1295 (No DAC)

Overview

CJC-1295 without DAC (also known as Modified GRF 1-29 or Mod GRF) is a synthetic 29-amino acid peptide analog of growth hormone-releasing hormone (GHRH). It was developed by ConjuChem Biotechnologies through structural modification of native GHRH to improve stability and metabolic half-life.

The peptide contains four amino acid substitutions compared to native GHRH: Ala2→D-Ala, Asn8→Gln, Ala15→Leu, and Met27→Leu. These modifications were specifically designed to resist degradation by dipeptidyl peptidase-IV (DPP-IV), the primary enzyme responsible for inactivating GHRH in vivo.

The peptide is commonly studied in combination with GH-releasing peptides (GHRPs) such as Ipamorelin, based on evidence suggesting synergistic GH release when GHRH analogs are paired with GHRP secretagogues. This combination approach has become standard in GH research protocols.

DAC vs No DAC: Understanding the Two Versions

One of the most common sources of confusion in the peptide research space is the distinction between CJC-1295 with DAC and CJC-1295 without DAC (also called Mod GRF 1-29). Although they share a name, these are functionally different compounds with very different pharmacokinetic profiles, dosing schedules, and GH release patterns. Understanding this distinction is essential for anyone reading the research literature.

What Is DAC?

DAC stands for Drug Affinity Complex. It is a chemical modification, specifically, a reactive lysine residue that binds covalently to serum albumin after injection. Albumin is a large, long-lived blood protein. Once CJC-1295 binds to albumin, it is protected from enzymatic degradation and renal clearance, dramatically extending its circulating half-life from approximately 30 minutes to over 6–8 days.

This technology was developed by ConjuChem Biotechnologies specifically to create a long-acting GHRH analog that would require only weekly (or less frequent) dosing, a significant advantage for pharmaceutical development and patient compliance.

What Is No DAC (Mod GRF 1-29)?

CJC-1295 without DAC retains the same 29-amino acid peptide sequence with the four stabilizing amino acid substitutions (D-Ala2, Gln8, Leu15, Leu27), but it does not include the albumin-binding Drug Affinity Complex. Without albumin binding, the peptide circulates freely and is cleared relatively quickly, with a half-life of approximately 30 minutes.

This shorter half-life means each injection produces a discrete, time-limited pulse of GH release rather than sustained elevation, and this is actually the reason many researchers prefer it.

Head-to-Head Comparison

Why Would a Researcher Choose No DAC?

The No DAC version is preferred in many research settings for several reasons:

• Physiological GH release: The body naturally releases GH in pulses, not as a constant stream. The No DAC version produces discrete GH spikes followed by a return to baseline, which more closely mimics this natural rhythm. Some researchers hypothesize that pulsatile release is more effective at activating downstream signaling pathways (including IGF-1 production) than sustained elevation.
• Reduced desensitization risk: Continuous receptor stimulation (as with the DAC version) may theoretically lead to GHRH receptor downregulation over time. Pulsatile stimulation allows receptors to reset between doses, potentially maintaining responsiveness over longer protocols.
• Synergy with GHRPs: The No DAC version's short action window makes it ideal for co-administration with GH-releasing peptides like Ipamorelin. Both can be injected simultaneously, producing a single amplified GH pulse. With the DAC version, this synergistic timing is less precise because the GHRH signal is always present.
• Finer dosing control: Multiple daily injections allow researchers to control exactly when GH pulses occur, for example, targeting the pre-sleep GH surge or post-exercise recovery windows.

Why Would a Researcher Choose DAC?

The DAC version has its own advantages:

• Convenience: One or two injections per week versus multiple daily injections is a significant practical advantage, particularly in clinical trial settings where compliance matters.
• Sustained IGF-1 elevation: The DAC version produces more consistent, sustained IGF-1 levels throughout the week. Some researchers believe this steady-state elevation may be beneficial for certain applications (e.g., body composition, recovery).
• More clinical data: Because ConjuChem pursued the DAC version for pharmaceutical development, it has more published clinical trial data. The safety and efficacy profile is better characterized.
• Simplicity: No need to time injections around meals, sleep, or exercise, the long half-life means the peptide is always active regardless of timing.

A Common Point of Confusion

In research community discussions, "CJC-1295" is often used ambiguously without specifying DAC or No DAC. This creates significant confusion because the two versions have fundamentally different pharmacokinetics. When reading research literature or protocols, always verify which version is being referenced. If a source describes once-weekly dosing, it almost certainly refers to the DAC version. If it describes multiple daily injections (especially in combination with Ipamorelin), it refers to the No DAC version (Mod GRF 1-29).

FDA / Regulatory Status

As of April 2026, CJC-1295 (No DAC) is not FDA-approved for any therapeutic indication.

CJC-1295 (No DAC) remains classified as a research peptide. ConjuChem Biotechnologies conducted early-stage clinical trials on CJC-1295 variants, but development efforts focused primarily on the DAC-modified version, which showed more favorable sustained GH and IGF-1 elevation in clinical studies. Development of the non-DAC version was ultimately discontinued.

No active IND (Investigational New Drug) applications are currently known for CJC-1295 (No DAC). The peptide exists primarily in research settings and should only be discussed in the context of scientific investigation and educational information.

Mechanism of Action

CJC-1295 (No DAC) acts as an agonist at the growth hormone-releasing hormone (GHRH) receptor on somatotroph cells in the anterior pituitary gland. It mimics the endogenous GHRH signal, triggering the release of growth hormone (GH) into the bloodstream.

The four amino acid substitutions in CJC-1295 (No DAC) provide resistance to DPP-IV enzymatic degradation. This extends the peptide's metabolic half-life from approximately 3-4 minutes (native GHRH) to approximately 30 minutes. However, this is substantially shorter than the CJC-1295 DAC variant (30+ hours), maintaining a more physiological, pulsatile GH release pattern.

A critical distinction: CJC-1295 does not directly stimulate GH release from the anterior pituitary independent of the endogenous neuroendocrine axis. Rather, it amplifies natural GHRH signaling and works within the hypothalamic-pituitary-somatotropic axis. GH release occurs in pulses, mimicking the endogenous GHRH secretion pattern.

Unlike exogenous GH administration, which can suppress endogenous GH production through negative feedback, GHRH analogs like CJC-1295 preserve and enhance the natural GH secretion pathway. This distinction is important for understanding its physiological role in research contexts.

Common Research Applications

CJC-1295 (No DAC) has been studied in several research contexts:

• Growth Hormone Optimization Research: Investigation of methods to enhance endogenous GH secretion patterns and amplitude, particularly in models of GH deficiency.
• Body Composition Studies: Examination of GH's role in lean mass accrual and fat mass reduction, conducted primarily in GH-deficient animal models and limited human data.
• Sleep Quality Research: Study of the relationship between GH pulses (which occur predominantly during slow-wave sleep) and sleep architecture.
• Recovery and Tissue Repair: Investigation of the indirect effects of GH stimulation on tissue remodeling and recovery, mediated through the GH/IGF-1 axis.
• Anti-Aging Research: Exploration of GH's role in age-related physiological decline, though human evidence remains limited and contested.
• Metabolic Research: Study of GH's effects on glucose metabolism, insulin sensitivity, and metabolic rate in research models.

Studied Benefits

Research on GHRH analogs and GH secretagogues has documented several physiological responses. It is important to note that most robust clinical data exists for GH replacement therapy and limited data for CJC-1295 specifically:

• Increased Pulsatile GH Release: Clinical studies demonstrated that CJC-1295 increases GH pulse amplitude and frequency, though the No DAC version produces more physiological, time-limited pulses compared to the DAC variant (Alba et al., 2006; Teichman et al., 2006).
• IGF-1 Elevation: As a consequence of increased GH secretion, circulating IGF-1 levels increase, contributing to GH's systemic effects.
• Body Composition Changes: In GH-deficient populations, GH restoration promotes lean mass accrual and fat mass reduction. Effects in eugonadal, non-deficient populations remain less well characterized.
• Sleep Architecture Improvement: GH pulses occur predominantly during slow-wave sleep stages. Some research suggests optimization of GH secretion supports sleep quality, though direct evidence in non-deficient subjects is limited.
• Enhanced Recovery: Indirect effects through the GH/IGF-1 axis may support tissue repair and recovery from exercise or injury, though mechanistic studies are ongoing.

Commonly Studied Dosing Protocols

While no FDA-approved dosing guidelines exist for CJC-1295 (No DAC), research protocols and investigational data suggest the following ranges:

The saturation dose concept suggests that GH responses plateau above a certain CJC-1295 dose, typically around 1 mcg/kg of body weight per injection. Additional increases beyond this threshold do not proportionally increase GH release.

Meal timing is particularly important: carbohydrate ingestion and elevated insulin suppress GHRH-stimulated GH release. For maximum GH secretion, injections are typically administered in a fasted state, with 30-60 minutes between injection and food intake.

Half-Life & Timing

CJC-1295 (No DAC) has an estimated metabolic half-life of approximately 30 minutes, substantially shorter than the DAC variant (30+ hours) but significantly longer than native GHRH (~3-4 minutes).

This ~30-minute half-life is actually considered advantageous by many researchers because it produces more physiological, pulsatile GH secretion patterns rather than the sustained, non-pulsatile elevation seen with the DAC variant. Peak GH levels typically occur 15-30 minutes post-injection and return to baseline within 60-90 minutes.

The shorter half-life allows for multiple injections per day to be spaced (typically 4-6 hours apart) without excessive overlap, maintaining distinct GH pulses that mirror the natural, pulsatile nature of endogenous GHRH secretion.

Optimal timing considerations:

• Upon Waking: GH levels naturally rise after sleep; injection timing here amplifies this natural rhythm.
• Before Bed: The largest natural GH pulse occurs during early slow-wave sleep; injection timing supports this nocturnal surge.
• Afternoon Administration: Some protocols include a mid-day injection to create multiple pulses, though the evidence for specific advantages is mixed.
• Exercise Timing: Moderate evidence suggests pre-exercise or post-exercise administration may enhance GH release, but direct comparative data in humans is limited.

Potential Side Effects

Based on limited clinical trial data and investigational use, CJC-1295 (No DAC) has been associated with the following adverse effects, generally reported as mild to moderate and transient. The table below summarizes commonly reported effects with incidence rates (where documented) and practical mitigation strategies discussed in research literature:

Note: These mitigation strategies are commonly discussed in research literature and community reports. They do not constitute medical advice. Consult a licensed healthcare professional before considering any peptide protocol.

Theoretical concerns include potential effects on carbohydrate metabolism, blood pressure changes, and cardiovascular stress, though direct evidence in short-term human studies is minimal.

Stacking Considerations

CJC-1295 (No DAC) is frequently studied in combination with other peptides and secretagogues to achieve synergistic GH release:

CJC-1295 + Ipamorelin

This is the most common and well-researched combination. Ipamorelin is a selective GH-releasing peptide (GHRP) that acts on a different receptor pathway (ghrelin receptor) than CJC-1295 (GHRH receptor). Combined administration produces amplified GH pulses that exceed either peptide alone. The synergistic effect is thought to result from complementary signaling: CJC-1295 stimulates GHRH receptors while Ipamorelin activates ghrelin signaling, creating a more robust hypothalamic drive for GH release.

For more detailed information on this combination protocol, see CJC-1295 + Ipamorelin Combination Guide.

CJC-1295 + Tesamorelin

Both are GHRH analogs, though with different structural modifications. Tesamorelin includes a GH-releasing hormone receptor binding domain modification. Combining two GHRH analogs is generally not recommended, as they activate the same receptor pathway and are unlikely to produce additive effects. However, limited research exists on this combination.

CJC-1295 + MK-677

MK-677 (Ibutamoren) is a non-peptide ghrelin mimetic and GH secretagogue. Some protocols combine CJC-1295 with MK-677 for sustained GH stimulation via complementary pathways. However, this combination is less studied than CJC-1295 + Ipamorelin.

CJC-1295 + IGF-1

Theoretically, combining GHRH analog with recombinant IGF-1 could provide both pulsatile GH stimulation and sustained IGF-1 elevation. However, this combination is rarely studied and presents potential concerns regarding feedback inhibition and metabolic effects.

Clinical Trial Status

CJC-1295 (No DAC) has limited clinical trial history compared to its DAC-modified analog:

ConjuChem Biotechnologies Trials

ConjuChem conducted Phase I and Phase II clinical trials on CJC-1295 variants. The primary focus shifted toward the DAC-modified version, which demonstrated sustained elevations in GH and IGF-1 over multiple days-a favorable pharmacokinetic profile for therapeutic dosing. Clinical efficacy and safety data were published for the DAC variant, but the non-DAC version received less emphasis in publication.

Published Clinical Data

Key published studies include:

• Ionescu et al. (2006): Demonstrated that CJC-1295 (primarily DAC variant) significantly increased plasma GH levels above baseline in healthy adult subjects.
• Alba et al. (2006): Reported GH-releasing effects of CJC-1295 in the Journal of Clinical Endocrinology & Metabolism, establishing efficacy in stimulating GH secretion.
• Teichman et al. (2006): Characterized the prolonged GH release profile of CJC-1295 DAC, emphasizing the distinction between DAC and non-DAC versions.

Current Status

No active clinical trials for CJC-1295 (No DAC) are currently listed on ClinicalTrials.gov. Development efforts were discontinued following focus on the DAC variant and subsequent pivot to other therapeutic areas. The non-DAC version exists primarily in research and educational contexts.

Frequently Asked Questions

1. What's the difference between CJC-1295 with DAC and without DAC?

The DAC (Drug Affinity Complex) is an additional amino acid modification that extends the half-life dramatically. CJC-1295 with DAC has a half-life of 30+ hours, allowing sustained GH elevation over days with once-weekly or twice-weekly dosing. CJC-1295 without DAC has a ~30-minute half-life, producing shorter, more physiological GH pulses with dosing required multiple times daily. Both are synthetic GHRH analogs, but they have different pharmacokinetic profiles and clinical applications. The non-DAC version is preferred by some researchers because pulsatile GH release more closely mimics natural secretion patterns.

2. Why is CJC-1295 combined with Ipamorelin?

CJC-1295 and Ipamorelin act on different signaling pathways: CJC-1295 activates GHRH receptors, while Ipamorelin activates ghrelin receptors. This complementary signaling produces amplified, synergistic GH release-greater than either peptide alone. The combination leverages two different stimulatory axes of the hypothalamic-pituitary-somatotropic system. This synergistic effect is well documented in research literature and has become standard in many GH optimization protocols.

3. Is CJC-1295 the same as GHRH?

No, CJC-1295 is a synthetic analog of GHRH, not identical to native GHRH. Native GHRH is rapidly degraded by DPP-IV enzyme, with a half-life of 3-4 minutes. CJC-1295 contains four amino acid substitutions that provide resistance to DPP-IV, extending its half-life to ~30 minutes (non-DAC) or 30+ hours (DAC). Both act on the same GHRH receptor, but the modified peptide is more resistant to enzymatic degradation and therefore more useful for research purposes.

4. Does CJC-1295 suppress natural GH production?

No. Unlike exogenous GH administration, which can suppress endogenous GH secretion through negative feedback mechanisms, GHRH analogs like CJC-1295 work within the endogenous neuroendocrine axis. CJC-1295 amplifies natural GHRH signaling and does not inhibit the hypothalamic-pituitary-somatotropic axis. Upon discontinuation, GH production should return to baseline patterns without a prolonged suppression period. However, very limited long-term data exists on this specific distinction.

5. What time of day is CJC-1295 typically studied?

CJC-1295 is commonly administered upon waking and before bed to align with natural GH secretion patterns. The largest endogenous GH pulse occurs during early slow-wave sleep, typically 1-3 hours after sleep onset. Upon waking, GH levels are elevated. Administering CJC-1295 at these times amplifies natural rhythm. Some protocols include a third daily injection during mid-afternoon. Exact timing optimization remains a subject of research, and individual responses vary.

6. How does CJC-1295 compare to direct GH administration?

Direct exogenous GH administration provides sustained, supraphysiological GH levels that suppress endogenous GH secretion and can disrupt the natural pulsatile pattern. CJC-1295 stimulates endogenous GH release, maintaining pulsatile secretion patterns and preserving the natural axis. CJC-1295 generally produces lower peak GH levels than exogenous GH but maintains more physiological dynamics. Direct GH has extensive clinical data (deficiency, aging, HIV wasting). CJC-1295 has more limited clinical data. The choice between them in research contexts depends on the specific research question and desired GH profile.

References