CJC-1295 no DAC

Overview

CJC-1295 no DAC is a synthetic analog of growth hormone-releasing hormone (GHRH). It consists of the first 29 amino acids of GHRH with four amino acid substitutions. Those substitutions make the molecule more resistant to enzymatic breakdown. The variant is also called Modified GRF (1-29).

The defining feature is what is missing: the DAC group. DAC stands for Drug Affinity Complex, a modification that binds covalently to serum albumin. The no-DAC variant lacks that group. As a result, the half-life is short, on the order of minutes rather than days.

This is the central distinction from CJC-1295 with DAC. The two variants share much of the same name but differ materially in molecular weight (3367.9 vs 3647.2 Da) and in pharmacokinetic behaviour. Online sources often conflate them. They are not interchangeable in research design. A separate entry describes the DAC variant.

The available evidence for the no-DAC variant is limited. No human intervention studies have examined this variant specifically. Much of the research attributed to 'GRF 1-29' concerns sermorelin, the unmodified GHRH fragment. That distinction matters when evaluating sources.

Mechanism of action

CJC-1295 no DAC acts on the GHRH receptor (GHRH-R). The receptor sits on somatotroph cells in the anterior pituitary. Activation stimulates the synthesis and release of growth hormone. Without the DAC group, the activity window is shorter than that of the DAC variant.

GHRH receptor activation

• Binding to the GHRH receptor on somatotroph cells of the anterior pituitary.
• Stimulation of growth hormone synthesis and release.
• Complementary to a separate pathway, the GHS receptor (GHS-R1a), through which compounds such as Ipamorelin act.

Shorter-acting profile

• The four amino acid substitutions confer resistance to degradation by the enzyme DPP-IV.
• Without the albumin-binding DAC group, the compound stays in circulation for a shorter time.
• The shorter window is discussed in research as compatible with a more pulsatile pattern of growth hormone release. Pulsatile means in peaks, the way the body releases growth hormone naturally.

Pharmacological context

• A shorter-acting profile has different implications for research on growth hormone pulsatility than a longer-acting one.
• Changes in hormonal markers do not automatically translate into broader physiological conclusions.
• The distinction between the DAC and no-DAC variants is pharmacokinetically meaningful and should not be conflated in research interpretation.

Research findings

• GHRH-receptor activation is established for the broader class of GHRH analogs, including sermorelin and the DAC variant.
• Direct research on the no-DAC variant specifically remains limited.
• The no-DAC variant has a shorter duration of action than the DAC variant. This follows from the absence of the albumin-binding group.
• Forensic-analytical work has identified the variant in seized material, with an added N-terminal glycine described as a structural modification.

Mechanistic basis

• GHRH-receptor activation is established for the broader class of GHRH analogs, including sermorelin and the DAC variant.
• Direct research on the no-DAC variant specifically remains limited.

Pharmacokinetic profile

• The no-DAC variant has a shorter duration of action than the DAC variant. This follows from the absence of the albumin-binding group.

Identification and analysis

• Forensic-analytical work has identified the variant in seized material, with an added N-terminal glycine described as a structural modification.

Research context

CJC-1295 no DAC appears primarily in discussions of the growth hormone axis and pulsatile endocrine signalling. Interest is partly driven by pharmacokinetics: a shorter-acting profile is viewed by some researchers as a closer approximation of the natural pulsatile rhythm of growth hormone release.

A distinction applies here. Mechanistic interest is not the same as evidence maturity. For the no-DAC variant specifically, human intervention studies are absent. Much of the public discussion takes place outside peer-reviewed frameworks.

Confusion between the DAC and no-DAC variants is widespread, as is confusion with sermorelin, the unmodified GHRH fragment. Clear identification of which variant was used is therefore a precondition for sound source interpretation.

Open questions

Interest in pulsatile GH signalling is conceptually grounded, but translational evidence specific to this variant remains limited.

• No human intervention studies have examined the no-DAC variant specifically. For research groups this points to a clear next step: controlled studies that examine this variant on its own rather than under a shared name.
• Sources frequently confuse the no-DAC variant with the DAC variant and with sermorelin. Explicit reporting of the exact structure would improve comparability across studies.
• Comparative data between the DAC and no-DAC variants under controlled conditions are limited. Direct comparative research is a logical next step.
• The relationship between a pulsatile release pattern and physiological outcomes is incompletely characterised. Translational research is needed here.
• The long-term profile of repeated GHRH-R activation has not been well established. Longitudinal research would help to fill that gap.

Research outlook

Controlled studies that examine the no-DAC variant on its own, separately from the DAC variant and sermorelin.

Comparative research between pulsatile and sustained growth hormone elevation, with functional endpoints.

Combination research with agents acting through the GHS receptor under defined conditions.

Clarification of the relationship between a pulsatile release pattern and outcomes further along the signalling chain.

Assessment of the long-term safety of repeated GHRH-R activation.

Scientific interest

Shorter-acting GHRH profile: conceptually linked to pulsatile patterns of growth hormone release.

Pharmacokinetically distinct from the DAC variant: a different research framework for the GH axis, owing to the absence of the albumin-binding group.

Resistance to enzymatic breakdown: the four substitutions that make the molecule more stable against DPP-IV.

An example of naming that obscures structure: a clear case for the importance of exact compound identification in research.

Specifications

References

1. Detection of stable carrier-bound modified GRF 1-29 (CJC-1295) by liquid chromatography high-resolution mass spectrometry in equine and human plasma · Gajda PM, Holtzman JL, Knych HK et al. · Drug Testing and Analysis · 2018
2. Advances in the detection of growth hormone releasing hormone synthetic analogs · Memdouh S, Gavrilović I, Ng K et al. · Drug Testing and Analysis · 2022

Availability

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