CJC-1295: Growth Hormone Research Guide [2026]

CJC-1295: What the Research Shows

CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH) that has become one of the most studied peptides in growth hormone axis research. Developed through modification of the first 29 amino acids of native GHRH (known as GRF 1-29 or Sermorelin), CJC-1295 incorporates four amino acid substitutions that dramatically extend its biological half-life from minutes to days.

This extended duration of action allows CJC-1295 to produce sustained, pulsatile growth hormone release that more closely mimics the body’s natural GH secretion pattern. Combined with its favorable pharmacokinetic profile, CJC-1295 has become a cornerstone compound for researchers investigating the GH-IGF-1 axis and its effects on body composition, metabolism, and tissue repair. Proxiva Labs offers CJC-1295 No DAC for qualified researchers, with all lots verified through our third-party testing program.

Growth Hormone Axis Biology

Understanding the hypothalamic-pituitary-GH axis is essential context for CJC-1295 research.

The GHRH-Somatostatin Balance

Growth hormone secretion is regulated by two hypothalamic hormones with opposing effects: GHRH stimulates GH release, while somatostatin (SRIF) inhibits it. The interplay between these signals creates the characteristic pulsatile GH secretion pattern — major secretory bursts (primarily during deep sleep) interspersed with periods of low GH levels.

Ghrelin and the GHS-R

A third regulatory input comes from ghrelin and synthetic growth hormone secretagogues (GHSs) that act through the GHS receptor (GHS-R1a). Compounds like Ipamorelin mimic ghrelin’s GH-releasing effects through this distinct receptor pathway, which is why CJC-1295 and Ipamorelin are frequently studied together — they activate complementary pathways for synergistic GH release.

The GH-IGF-1 Cascade

Released GH acts on the liver and peripheral tissues to stimulate insulin-like growth factor-1 (IGF-1) production. IGF-1 mediates many of GH’s anabolic effects including protein synthesis, cell proliferation, and tissue growth. IGF-1 also provides negative feedback to the hypothalamus and pituitary, helping regulate the overall axis. CJC-1295’s effects on this cascade are measured through both GH levels and IGF-1 as downstream markers.

CJC-1295 Mechanism of Action

Modified GRF 1-29 Structure

CJC-1295 is based on GRF 1-29 (the first 29 amino acids of GHRH that retain full biological activity) with four key amino acid substitutions at positions 2, 8, 15, and 27. These substitutions were specifically engineered to resist enzymatic degradation by dipeptidyl peptidase-IV (DPP-IV), the enzyme primarily responsible for rapid GHRH inactivation in vivo.

The substitutions (Ala2?D-Ala, Asn8?Gln, Ala15?Ala(Me), Met27?Leu) maintain receptor binding affinity while extending the peptide’s half-life from approximately 7 minutes (native GHRH) to approximately 30 minutes (modified GRF 1-29) (Teichman et al., 2006).

CJC-1295 with DAC vs Without DAC

A critical distinction in CJC-1295 research is the Drug Affinity Complex (DAC) modification.

CJC-1295 DAC

The DAC version incorporates a maleimidopropionic acid (MPA) linker that forms a covalent bond with serum albumin upon injection. This albumin conjugation extends the half-life to approximately 5-8 days, creating sustained GH elevation rather than pulsatile release. The original clinical study showed that a single CJC-1295 DAC injection increased GH levels for up to 6 days and IGF-1 for up to 14 days (Teichman et al., 2006).

CJC-1295 No DAC (Modified GRF 1-29)

CJC-1295 without DAC has a shorter half-life (~30 minutes) and produces GH pulses more similar to natural physiological patterns. Many researchers prefer this form because it preserves the pulsatile GH release pattern, which is considered important for maintaining normal GH receptor sensitivity and downstream signaling.

Practical Differences

Effects on GH Pulsatility and IGF-1

The landmark clinical study by Teichman et al. (2006) remains the primary pharmacokinetic reference for CJC-1295. Key findings included:

• Single SC injection of CJC-1295 DAC (30-60 mcg/kg) increased mean GH concentrations by 2-10 fold
• IGF-1 levels increased by 1.5-3 fold, peaking at day 2-3 and remaining elevated for up to 14 days
• GH pulsatility was maintained with the DAC version, though pulse amplitude was significantly increased
• Dose-dependent responses were observed across 30, 60, and 90 mcg/kg dose groups
• No significant changes in glucose, insulin, cortisol, prolactin, or thyroid hormones at studied doses

Body Composition Research

The sustained GH and IGF-1 elevation produced by CJC-1295 has significant implications for body composition research.

Lipolysis and Fat Reduction

Growth hormone is one of the most potent lipolytic hormones, acting through hormone-sensitive lipase (HSL) activation in adipocytes. Sustained GH elevation from CJC-1295 promotes continuous fatty acid mobilization and oxidation, particularly from visceral adipose depots. Animal studies with GHRH analogs have consistently shown reduced adiposity without caloric restriction.

Lean Mass Effects

GH and IGF-1 promote protein synthesis, nitrogen retention, and satellite cell activation in skeletal muscle. Research with GHRH analogs has demonstrated improvements in lean body mass, which combined with fat reduction creates a favorable shift in body composition ratio.

Sleep and Recovery Research

Approximately 70% of daily GH secretion occurs during slow-wave (deep) sleep, and GHRH itself has been shown to promote slow-wave sleep. CJC-1295 research intersects with sleep science through this GH-sleep connection. Studies with GHRH analogs have shown increased slow-wave sleep duration and improved sleep quality metrics, which may secondarily enhance recovery and tissue repair processes (Steiger et al., 1998).

CJC-1295 + Ipamorelin Combination

The combination of CJC-1295 with Ipamorelin is one of the most widely studied peptide combinations in GH research.

Mechanistic Synergy

CJC-1295 activates the GHRH receptor on somatotroph cells, while Ipamorelin activates the GHS receptor (ghrelin receptor). These two receptor systems converge on different intracellular signaling pathways that synergistically amplify GH release. Additionally, ghrelin receptor activation suppresses somatostatin release, removing the inhibitory brake on GH secretion while CJC-1295 provides the stimulatory drive.

Selectivity Advantage

Ipamorelin is notably selective among GH secretagogues — it stimulates GH release without significantly affecting cortisol, prolactin, or ACTH levels, unlike older GHSs like GHRP-6 and GHRP-2. Combined with CJC-1295’s clean hormonal profile, the combination provides targeted GH axis stimulation with minimal off-target endocrine effects.

Comparison with Other GH Secretagogues

• Tesamorelin — FDA-approved GHRH analog for lipodystrophy. Similar mechanism to CJC-1295 but with different structural modifications and dosing requirements.
• Sermorelin — Original GRF 1-29 without protective substitutions. Shorter half-life (~7 min) requires more frequent dosing. Less potent than CJC-1295 per injection.
• GHRP-6 — Potent GH secretagogue but stimulates hunger (ghrelin-like appetite effects) and can elevate cortisol and prolactin.
• AOD 9604 — GH fragment that promotes lipolysis without GH-axis stimulation. Different mechanism entirely (beta-3 adrenergic) but complementary for body composition research.

Research Protocols

• CJC-1295 DAC clinical dosing: 30-60 mcg/kg SC, 1-2x per week (Teichman et al.)
• CJC-1295 No DAC: 1-2 mcg/kg SC per administration, 1-3x daily in preclinical models
• CJC-1295 + Ipamorelin: Typically co-administered at time of injection; common research timing is pre-sleep to align with physiological GH surge
• Storage: Lyophilized powder at -20°C; reconstituted with bacteriostatic water, stored at 4°C for up to 4 weeks

Safety Profile

Clinical data from the Teichman study showed CJC-1295 was generally well-tolerated:

• Most common adverse event: injection site reactions (erythema, swelling)
• Transient facial flushing reported in some subjects
• Mild headache in a subset of participants
• No clinically significant changes in glucose metabolism, insulin sensitivity, or other endocrine parameters at studied doses
• No serious adverse events attributed to the study drug

Frequently Asked Questions

What is the difference between CJC-1295 and Sermorelin?

Both are based on GRF 1-29, but CJC-1295 has four amino acid substitutions that protect it from DPP-IV degradation, extending its half-life from ~7 minutes (Sermorelin) to ~30 minutes (CJC-1295 No DAC) or 5-8 days (CJC-1295 DAC).

Why combine CJC-1295 with Ipamorelin?

They activate different receptor systems (GHRH-R and GHS-R) that synergistically amplify GH release. The combination also provides cleaner stimulation — Ipamorelin is selective for GH without raising cortisol or prolactin.

Does CJC-1295 affect sleep?

GHRH and its analogs have been shown to promote slow-wave sleep in research studies. Since most GH is secreted during deep sleep, the relationship between CJC-1295 and sleep quality is an active area of investigation.

Conclusion

CJC-1295 remains one of the most well-characterized peptides for growth hormone axis research. Its extended half-life, dose-dependent GH and IGF-1 elevation, and synergistic potential with GHS-receptor agonists like Ipamorelin make it an essential tool for investigators studying body composition, metabolic health, and the GH-IGF-1 axis.

Explore CJC-1295 No DAC, Ipamorelin, and our complete research peptide catalog. Visit the research hub for ongoing updates.