CJC-1295

Overview

CJC-1295 is a synthetic peptide analog of growth hormone releasing hormone (GHRH), originally developed by ConjuChem Biotechnologies (now Aeterna Zentaris) in the early 2000s. It was designed to overcome the primary limitation of native GHRH(1-29) — rapid enzymatic degradation that results in a plasma half-life of only 5–7 minutes.

CJC-1295 exists in two distinct forms that are frequently confused in community discussions:

CJC-1295 with DAC (Drug Affinity Complex) — The original pharmaceutical compound. The DAC moiety is a reactive chemical group (maleimidopropionic acid) that forms a covalent bond with serum albumin after injection, extending the half-life to approximately 6–8 days. This produces sustained, non-pulsatile GH elevation.

CJC-1295 without DAC (also called Modified GRF 1-29 or Mod GRF 1-29) — A 29-amino-acid GHRH analog with four amino acid substitutions that improve protease resistance without the albumin-binding DAC component. Half-life is approximately 30 minutes. This version produces pulsatile GH release more closely resembling natural physiology.

The distinction between these two forms is critical. In practice, most research community discussion of "CJC-1295" refers to the no-DAC version (Mod GRF 1-29), which is the form typically paired with GHRPs such as Ipamorelin.

Amino Acid Sequence

CJC-1295 no DAC (Mod GRF 1-29)

A modified 29-amino-acid fragment of GHRH(1-44) with four substitutions:

Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-NH₂

Key substitutions from native GHRH(1-29):

• Position 2: Ala → D-Ala (protease resistance)

• Position 8: Asn → Gln (deamidation resistance)

• Position 15: Gly → Ala (improved stability)

• Position 27: Met → Leu (oxidation resistance)

• Molecular weight: ~3,367 g/mol

• CAS Number: 863288-34-0

CJC-1295 with DAC

The same 29-amino-acid core with a maleimidopropionic acid-lysine linker that reacts with Cys34 of serum albumin in vivo.

• Molecular weight: ~3,647 g/mol (before albumin conjugation)

Mechanism of Action

GHRH Receptor Agonism

CJC-1295 binds to the GHRH receptor (GHRHR) on somatotroph cells in the anterior pituitary gland. Activation of GHRHR triggers:

• Stimulation of the cAMP/PKA signaling cascade
• Transcription of the GH gene (GH1)
• Synthesis of new growth hormone
• Priming of GH-containing secretory granules for release

This mechanism is distinct from and complementary to GHRPs like Ipamorelin, which trigger release of already-stored GH through the GHS-R1a receptor.

DAC vs. No-DAC Pharmacodynamics

The two versions produce fundamentally different GH release patterns:

With DAC: The albumin conjugation creates a sustained circulating reservoir. GH levels remain elevated above baseline for 6–10 days after a single injection. This produces a "GH bleed" — continuous moderate elevation without distinct pulses — which is pharmacologically different from natural GH secretion patterns.

Without DAC (Mod GRF 1-29): The 30-minute half-life produces a discrete GH pulse lasting approximately 2–3 hours. When timed appropriately (particularly before sleep or combined with a GHRP), this closely mimics the natural nocturnal GH pulse pattern.

Synergy with GHRPs

The mechanistic basis for combining CJC-1295 (no DAC) with GHRPs is well-established:

• GHRH analogs prime the pituitary and initiate GH synthesis
• GHRPs amplify the release signal and suppress somatostatin
• The combined effect is supraadditive (synergistic), producing GH pulses 2-3 times greater than either agent alone. See stacking fundamentals for general combination principles

Somatostatin Sensitivity

Unlike GHRPs, GHRH analogs including CJC-1295 are sensitive to somatostatin inhibition. GH release in response to CJC-1295 is blunted when somatostatin tone is high (e.g., after food intake, particularly high-fat meals). This is why co-administration with a GHRP — which opposes somatostatin — is considered mechanistically important.

Research Summary

Area of Study	Key Finding	Notable Reference
Half-life extension (DAC)	Single injection maintained elevated GH levels for 6–10 days in healthy subjects	Teichman et al., Journal of Clinical Endocrinology & Metabolism, 2006
IGF-1 elevation (DAC)	Sustained IGF-1 elevation of 1.5–3x baseline for 9–11 days after single dose	Teichman et al., JCEM, 2006
Dose-response (DAC)	Linear dose-response with doses of 30, 60, and 90 μg/kg in human subjects	Teichman et al., JCEM, 2006
Combination with GHRP	Synergistic GH release when GHRH analogs combined with GHRPs; supraadditive response	Bowers, JCEM, 1998
Body composition	Increased lean body mass and decreased fat mass in GH-deficient models	Jette and Bhatt, ConjuChem corporate data, 2004
Pulsatile release (no DAC)	Mod GRF 1-29 preserves physiological GH pulse patterns when dosed intermittently	Thorner et al., JCEM, 1986
Safety (DAC)	Phase II clinical trial terminated after death of a subject (attributed to myocardial infarction, unrelated to compound per investigators)	ConjuChem/Aeterna Zentaris, 2006
Stability improvement	Four amino acid substitutions increased half-life from ~7 minutes (native GHRH) to ~30 minutes (Mod GRF 1-29)	Various, established in GHRH analog literature

Pharmacokinetics

CJC-1295 with DAC

• Half-life: 6–8 days (albumin-bound)
• Peak GH elevation: 2–10 hours post-injection
• Duration of GH elevation: 6–10 days
• IGF-1 elevation: Sustained for 9–11 days
• Route: Subcutaneous injection
• Dosing frequency: Weekly or less in clinical studies

CJC-1295 without DAC (Mod GRF 1-29)

• Half-life: ~30 minutes
• Peak GH elevation: 15–30 minutes post-injection
• Duration of GH pulse: 2–3 hours
• Route: Subcutaneous injection
• Dosing frequency: 1-3 times daily in research protocols (often paired with a GHRP)
• Dosing timing recommendation: Administer on an empty stomach; food blunts the GH response due to elevated somatostatin

Dosing Protocols

The following dosing information is compiled from published research and community discussion for educational purposes only. No FDA-approved human dosing guidelines exist for most research peptides. Always consult a qualified healthcare professional.

Reconstitution

Parameter	Value
Vial size	5 mg
Bacteriostatic water	3.0 mL
Concentration	~1,667 mcg/mL
Storage (reconstituted)	2-8 °C, use within 1-2 weeks
Storage (lyophilized)	-20 °C

Dosing Schedule

Phase	Dose	Frequency	Duration
Starting	100-150 mcg	Once daily	Weeks 1-2
Mid-range	200 mcg	Once daily	Weeks 3-6
Target	250-300 mcg	Once daily	Weeks 7-12

Syringe Measurements (U-100 insulin syringe)

Dose	Units	Volume
100 mcg	6 units	0.06 mL
150 mcg	9 units	0.09 mL
200 mcg	12 units	0.12 mL
300 mcg	18 units	0.18 mL

Cycle Guidelines

• Cycle length: 8-12 weeks (up to 16 weeks)
• Route: Subcutaneous injection
• Timing: Bedtime preferred to align with natural nocturnal GH secretion
• Fasting: Administer on an empty stomach; food blunts the GH response
• Titration: Increase by ~50 mcg every 1-2 weeks
• Injection sites: Rotate between abdomen, thighs, and upper arms

Common Discussion Topics

1. DAC vs. no-DAC confusion — The single most common source of confusion in community discussions. The two forms have fundamentally different pharmacokinetics and use cases. Most community protocols reference the no-DAC version.

2. Pairing with Ipamorelin — The "CJC/Ipa" combination is arguably the most widely discussed GH secretagogue stack. See Ipamorelin for details on the complementary mechanism.

3. Pulsatile vs. sustained GH — Debate over whether the DAC version's sustained GH elevation is beneficial or potentially harmful compared to the physiological pulsatile pattern produced by the no-DAC version.

4. Timing protocols — Common discussion around optimal injection timing: pre-bed (to amplify the natural nocturnal GH pulse), morning fasted, and post-training.

5. Saturation dose — Community discussion suggests that the GH response to Mod GRF 1-29 plateaus at approximately 100 mcg per injection (the "saturation dose"), beyond which additional peptide does not produce proportionally more GH.

6. Comparison with Sermorelin — Both are GHRH analogs, but CJC-1295 no DAC is considered more stable and potent than Sermorelin due to its amino acid substitutions.

Related Compounds

• Ipamorelin — the most common GHRP partner for CJC-1295 no DAC
• Sermorelin — an earlier GHRH analog with FDA history; shorter-acting and less stable than Mod GRF 1-29
• GHRP-6 — an alternative GHRP partner with stronger appetite stimulation
• GHRP-2 — another GHRP option with intermediate selectivity
• Tesamorelin — an FDA-approved GHRH analog (for HIV-associated lipodystrophy) structurally related to CJC-1295
• MK-677 (Ibutamoren) — an oral non-peptide GHS-R1a agonist sometimes used as an alternative to injectable GHRP+GHRH combinations