MOD GRF 1-29 (CJC-1295 Without DAC) is a tetrasubstituted GHRH(1-29) analog with ~30-minute half-life — the most commonly used short-acting GHRH compound for pulsatile GH secretion research.
Product definition
What is MOD GRF 1-29?
MOD GRF 1-29 (CJC-1295 Without DAC) is a tetrasubstituted GHRH(1-29) analog with ~30-minute half-life — the most commonly used short-acting GHRH compound for pulsatile GH secretion research.
MOD GRF 1-29 is the pharmacological name for the tetrasubstituted GHRH(1-29) peptide. The 'MOD' prefix indicates the four protective modifications: Aib at position 2 (DPP-IV resistance), Gln at position 8 (neutral endopeptidase protection), Ala at position 15 (backbone stability), and Nle at position 27 (methionine oxidation prevention). These modifications are collectively responsible for the pharmacokinetic improvement versus native GHRH while preserving receptor binding and signaling.
The compound is also commercially designated CJC-1295 Without DAC — the same peptide referenced by the ConjuChem nomenclature used in research supply contexts. For researchers cross-referencing the pharmacological literature versus commercial product catalogs, MOD GRF 1-29 and CJC-1295 Without DAC are fully interchangeable terms for the same molecule.
In the GH secretagogue research literature, MOD GRF 1-29 is studied both as a standalone GHRH agonist (characterizing GHRH receptor pharmacology) and in combination with GHRPs (characterizing the synergistic GHRH+GHRP GH amplification effect). Its 30-minute half-life and preserved pulsatile kinetics make it the default short-acting GHRH reference compound.
Research context
How is MOD GRF 1-29 described in the research literature?
MOD GRF 1-29 activates GHRH receptors on pituitary somatotropes with full agonism, producing pulsatile GH release via cAMP signaling. Four protective substitutions extend half-life from ~2 min to ~30 min by blocking DPP-IV and neutral endopeptidase cleavage. Synergistic with GHS-R1a agonists (ipamorelin) through mechanistically independent GH amplification.
Compound profile
Key facts about MOD GRF 1-29
- Class
- Modified GHRH analog (tetrasubstituted GHRH(1-29))
- Also known as
- CJC-1295 Without DAC, GRF(1-29)NH2
- Amino acids
- 29 (with 4 protective substitutions)
- Molecular weight
- ~3,367 Da
- Half-life
- ~30 minutes in vivo
- Research category
- GH axis, pulsatile GH protocols, GHRH pharmacology
- Storage
- Lyophilized: −20°C. Reconstituted: 2–8°C, use within 30 days
Research areas
What research areas is MOD GRF 1-29 associated with?
- Identical to CJC-1295 Without DAC — the most commonly used short-acting GHRH analog in GH research protocols
- Full GHRH receptor agonism retained — same receptor binding and GH signaling as native GHRH
- ~30-minute half-life enables pulsatile GH research with physiologically relevant pulse dynamics
- Four protective substitutions address DPP-IV, neutral endopeptidase, and oxidation vulnerabilities
- Synergistic with ipamorelin for combined GHRH+GHRP GH pulse amplification protocols
- The pharmacologically correct designation for literature cross-referencing across both naming conventions
Research audience
Who researches MOD GRF 1-29?
MOD GRF 1-29 is used by researchers in GH axis pharmacology, GHRH receptor biology, pituitary somatotrope function, and GH secretagogue combination research. It is the standard GHRH component for researchers who are cross-referencing pharmacological literature (where 'MOD GRF 1-29' is the primary designation) with commercial research supply sources.
Preclinical research overview
What does the preclinical literature say about MOD GRF 1-29?
The pharmacological development of MOD GRF 1-29 represents the systematic application of protective amino acid substitution technology to native GHRH(1-29) — the same approach used in semaglutide (position-8 Aib substitution for DPP-IV resistance) applied to the GHRH scaffold. The specific substitutions were chosen based on known enzymatic cleavage sites in native GHRH: DPP-IV cleavage at His-Ala at positions 1-2, neutral endopeptidase action at position 8, and oxidative methionine degradation at position 27.
In GH pulse biology research, MOD GRF 1-29 is used to study how GHRH receptor activation patterns affect somatotrope GH secretion. The pulsatile kinetics (on for ~30 min, then cleared) allow researchers to characterize the GH response to a defined, time-limited GHRH receptor stimulus — useful for studies of somatotrope desensitization, GHRH receptor downregulation, and the pulse frequency effects on downstream IGF-1.
For combination GHRH+GHRP research (the 2X Blend design), MOD GRF 1-29 is the GHRH component that pairs with ipamorelin. The mechanistic model is: GHRH receptor activation recruits additional somatotropes and increases their responsiveness (the 'priming' effect); GHS-R1a activation by ipamorelin then produces a larger GH release from the primed pool. The result is a synergistic GH pulse that exceeds either compound alone.
Common questions
Frequently asked about MOD GRF 1-29
Is MOD GRF 1-29 exactly the same as CJC-1295 Without DAC?
Yes — they are the same molecule. MOD GRF 1-29 is the pharmacological designation used in academic literature; CJC-1295 Without DAC is the commercial designation used in research supply markets. Both refer to the identical tetrasubstituted GHRH(1-29) peptide with Aib at position 2, Gln at position 8, Ala at position 15, and Nle at position 27. When Peptific stocks CJC-1295 Without DAC, it is the same compound as MOD GRF 1-29 in every pharmacological sense.
Why does the naming distinction matter for research?
When cross-referencing pharmacological literature, searches for 'MOD GRF 1-29' or 'Modified GRF(1-29)' will locate the mechanistic characterization studies; searches for 'CJC-1295 Without DAC' will locate research supply and protocol-focused literature. Understanding both designations allows researchers to aggregate the full published dataset across both naming conventions — which collectively represents the most extensive literature on any short-acting GHRH analog currently in research use.
Should MOD GRF 1-29 be used with a GHRP?
Not required, but in most GH axis research protocols, MOD GRF 1-29 is combined with a GHRP (ipamorelin being the standard) to produce synergistic GH pulse amplification. As a standalone compound, it produces GH pulses via GHRH receptor activation alone. In combination with ipamorelin, the same GHRH dose produces significantly larger GH pulses — the basis of the 2X Blend protocol. Whether to include a GHRP depends on whether the research question involves GHRH receptor pharmacology in isolation or combined GHRH+GHRP GH dynamics.
Research Use Only
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