CJC-1295 Without DAC: Complete Research Guide to the Short-Acting GHRH Analogue

CJC-1295 Without DAC is one of the foundational compounds in growth hormone peptide research. As a synthetic analogue of growth hormone-releasing hormone (GHRH), it stimulates the pituitary gland to produce and secrete GH in a pulsatile pattern that closely mirrors endogenous GH physiology — making it among the most physiologically relevant tools available for GH axis research.

This guide is a standalone deep dive into CJC-1295 Without DAC — its molecular structure, receptor pharmacology, mechanisms of GH stimulation, downstream effects, comparison to related compounds, and laboratory protocols. Researchers already familiar with the general GH axis landscape will find the mechanistic and comparative detail they need here to refine their experimental designs.

All content is for educational and research purposes only. CJC-1295 Without DAC is designated for research use only and is not approved for human or veterinary use.

What Is CJC-1295 Without DAC?

CJC-1295 Without DAC is a synthetic 30-amino acid peptide analogue of human GHRH (1-29). Human GHRH is a 44-amino acid hypothalamic peptide that stimulates anterior pituitary somatotrophs to synthesise and release growth hormone. The native peptide is rapidly inactivated by dipeptidyl peptidase IV (DPP-IV), giving it a plasma half-life of under 7 minutes — too short for practical research use without continuous infusion.

CJC-1295 Without DAC incorporates several amino acid substitutions that confer resistance to DPP-IV cleavage, extending its functional half-life to approximately 20–30 minutes while maintaining high-affinity binding to GHRH receptors (GHRHR). This makes it practical for research use while preserving the pulsatile GH release kinetics that define physiological GH secretion.

  • Structure: 30-amino acid synthetic GHRH analogue
  • Half-life: ~20–30 minutes (no albumin binding)
  • GH release pattern: Pulsatile — mirrors endogenous GHRH rhythm
  • Receptor: GHRHR (class B GPCR) on anterior pituitary somatotrophs
  • Supply form: Lyophilized powder, ≥99% purity

Proto Peptide supplies CJC-1295 Without DAC 5mg for laboratory research across Canada and the USA. It is also available as part of the Gold Standard Stack with Ipamorelin.

Mechanism of Action: GHRH Receptor Pharmacology

GHRHR Structure and Signalling

The GHRH receptor (GHRHR) is a class B G-protein coupled receptor (GPCR) expressed predominantly on somatotroph cells of the anterior pituitary. Class B GPCRs are characterised by a large extracellular N-terminal domain that forms the primary peptide ligand binding site.

When CJC-1295 Without DAC binds GHRHR:

  1. Gs coupling activates adenylyl cyclase → intracellular cAMP rises
  2. cAMP activates Protein Kinase A (PKA) → phosphorylates CREB and other transcription factors
  3. Transcriptional activation → upregulates GH gene expression
  4. Membrane depolarisation and Ca²⁺ influx → triggers GH granule exocytosis from somatotroph secretory vesicles
  5. GH pulse enters systemic circulation → acts directly on peripheral tissues and stimulates hepatic IGF-1 production

Why Pulsatility Matters

A critical feature of CJC-1295 Without DAC's short half-life — often mischaracterised as a limitation — is actually its primary physiological advantage for research. Endogenous GH secretion is pulsatile: large pulses during slow-wave sleep, smaller pulses throughout the day, with troughs near zero between peaks. This pulsatility is not incidental — it is the pattern to which GH receptors in peripheral tissues are calibrated. Continuous GH elevation (as occurs with the DAC version or exogenous GH) desensitises GH receptors and can impair the very signalling it attempts to stimulate.

CJC-1295 Without DAC preserves this pulsatility. Each administration produces a discrete GH pulse, after which GH returns to baseline — maintaining receptor sensitivity and the physiological GH rhythm in research models.

Somatostatin Regulation

GH secretion is regulated by a negative feedback system involving somatostatin, a hypothalamic peptide that inhibits GH release. CJC-1295 Without DAC stimulates GH within this regulatory framework — the somatostatin feedback system remains intact. The magnitude of each GH pulse is therefore shaped by the endogenous somatostatin tone at the time of administration, providing a more physiologically representative model than approaches that bypass this regulation.

Downstream Effects of CJC-1295 Without DAC

IGF-1 Stimulation

The primary downstream mediator of CJC-1295's metabolic and anabolic effects is IGF-1 (insulin-like growth factor 1), produced in the liver in response to GH signalling. IGF-1 itself signals through the IGF-1 receptor (IGF-1R), a receptor tyrosine kinase that activates PI3K/Akt and MAPK/ERK pathways in target tissues.

Elevated IGF-1 mediates:

  • Protein synthesis and anabolic signalling in skeletal muscle
  • Lipolysis in adipose tissue (fat mobilisation)
  • Stimulation of bone formation via osteoblast activation
  • Cell proliferation and survival signalling in multiple tissue types

Lipolysis and Fat Metabolism

GH directly stimulates lipolysis in adipocytes through hormone-sensitive lipase activation. Increased GH pulse amplitude (as produced by CJC-1295) drives fatty acid mobilisation from visceral and subcutaneous fat depots. For researchers studying metabolic disease models, this lipolytic mechanism is a key variable.

Anabolic Signalling in Muscle

Through both direct GH receptor activation and downstream IGF-1/IGF-1R signalling, CJC-1295 promotes protein synthesis and nitrogen retention in muscle tissue. This makes it relevant for body composition research, sarcopenia models, and recovery biology studies.

CJC-1295 Without DAC vs. Related Compounds

vs. CJC-1295 With DAC

CJC-1295 With DAC incorporates a Drug Affinity Complex that enables covalent binding to plasma albumin, extending the half-life to approximately 7–8 days. This produces sustained, non-pulsatile GH elevation — a fundamentally different physiological model. With DAC is appropriate for studies requiring sustained GH exposure; Without DAC is appropriate for pulsatile GH research. Only CJC-1295 Without DAC is available on the Proto Peptide site (/products/cjc-1295-no-dac), as the pulsatile format is the preferred research tool.

vs. Sermorelin

Sermorelin is a shorter GHRH fragment (1–29 amino acids) without CJC-1295's stability-enhancing substitutions. Its ~10 minute half-life makes it even more rapidly cleared than CJC-1295 Without DAC. CJC-1295's amino acid substitutions confer superior DPP-IV resistance and receptor affinity.

vs. Tesamorelin

Tesamorelin is the full 44-amino acid GHRH sequence with an N-terminal trans-3-hexenoic acid modification. It has the most extensive clinical data of any GHRH analogue, particularly for visceral fat reduction. CJC-1295 Without DAC has comparable pulsatile kinetics to Tesamorelin but a shorter overall sequence. Choice between them depends on whether translatability to human clinical data (favouring Tesamorelin) or a more common research format (favouring CJC-1295) is the priority. Our full Tesamorelin guide covers the Tesamorelin profile in detail.

vs. Ipamorelin (Combination Partner)

Ipamorelin activates the ghrelin receptor (GHS-R1a) — a completely different receptor system from GHRHR. Combining CJC-1295 Without DAC (GHRHR agonist) with Ipamorelin (GHS-R1a agonist) activates both GH-stimulating receptor pathways simultaneously, producing a synergistic GH pulse larger than either compound alone. This is the basis of the Gold Standard Stack. See our Gold Standard Stack guide for the full mechanistic rationale.

Research Applications

Growth hormone axis characterisation: Dose-response studies of GHRHR activation; comparison of GH pulse amplitude and kinetics across experimental conditions.

Body composition research: GH/IGF-1-driven changes in lean mass, fat mass, and lipid metabolism in diet-induced obesity, sarcopenia, and body composition models.

Recovery and tissue repair biology: GH's role in fibroblast activation, collagen synthesis, and connective tissue repair makes CJC-1295 relevant in post-injury recovery models.

Anti-aging and longevity research: The GH/IGF-1 axis declines with age; CJC-1295 is used to examine restoration of GH pulsatility in aged animal models and its effects on aging biomarkers.

Combination GH protocols: CJC-1295 is the standard GHRH component in dual GHRH/GHRP research designs — always with a GHRP like Ipamorelin as a co-stimulant.

Reconstitution and Storage

CJC-1295 Without DAC is water-soluble and reconstitutes readily in bacteriostatic water.

Reconstitution:

  1. Equilibrate sealed vial to room temperature (15–30 min)
  2. Wipe stopper with alcohol; allow 30 seconds to dry
  3. Draw target BAC water volume; inject slowly down the inner vial wall
  4. Swirl gently; inspect for clarity (should be clear and colourless)

Storage:

  • Lyophilized: -20°C, dark and dry, 24+ months
  • Reconstituted: 2–8°C, 4–6 weeks; aliquot to prevent freeze-thaw cycling

Use Proto Peptide's Bacteriostatic Water (Hospira 30mL) and Syringe Bundle.

Frequently Asked Questions

Why is CJC-1295 Without DAC preferred over the DAC version for most research? Pulsatile GH release — preserved by the short-acting Without DAC version — is the physiologically normal pattern. Pulsatility maintains GH receptor sensitivity and the regulatory somatostatin feedback loop. Continuous GH elevation (DAC version) desensitises receptors and bypasses physiological regulation.

How does CJC-1295 Without DAC produce a bigger GH pulse than native GHRH? Native GHRH is inactivated within 7 minutes by DPP-IV. CJC-1295's amino acid substitutions extend this to 20–30 minutes, allowing more sustained GHRHR occupation and a consequently larger GH secretory response per administration.

Is CJC-1295 Without DAC the same as "Modified GRF (1-29)"? Yes — these names are used interchangeably in research literature. "Modified GRF 1-29" reflects the 1-29 amino acid sequence of GHRH with modification (the CJC-1295 substitutions). CJC-1295 Without DAC is the commercial designation.

Can CJC-1295 Without DAC be combined with GLP-family compounds? Yes — researchers have studied CJC-1295 alongside GLP compounds to examine the interplay between GH axis stimulation and incretin-mediated metabolic effects. These are complementary mechanisms affecting body composition from different angles.

Conclusion

CJC-1295 Without DAC is the gold standard GHRH analogue for pulsatile GH research — stable enough to be practical, short-acting enough to preserve physiological GH rhythmicity, and well-characterised enough to serve as a benchmark compound in GH axis studies. Its combination with Ipamorelin (the Gold Standard Stack) remains the most widely referenced dual-pathway GH protocol in the research literature.

Proto Peptide supplies CJC-1295 Without DAC 5mg and the Gold Standard Stack for Canadian and US researchers. Browse our full catalog.

This content is intended for informational and educational purposes only. All products are for research use only and are not approved for human or veterinary use. Statements have not been evaluated by the FDA or Health Canada. Always follow your institution's guidelines before handling any research chemical.

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