CJC-1295
Also known as: CJC-1295 DAC, Modified GRF 1-29, Drug Affinity Complex
CJC-1295 is a synthetic analog of growth hormone releasing hormone (GHRH) with a Drug Affinity Complex that extends its half-life significantly compared to native GHRH.
Key Findings at a Glance
- •The Drug Affinity Complex modification allows CJC-1295 to covalently bond to serum albumin after injection, extending its half-life from minutes to 6 to 8 days.
- •A single injection of CJC-1295 with DAC can elevate IGF-1 levels for up to two weeks, a duration unmatched by any other GHRH analog studied in clinical settings.
- •CJC-1295 combined with a GHRP such as Ipamorelin or GHRP-6 produces 2 to 5 times more growth hormone than either peptide alone, due to activation of complementary pituitary pathways.
- •CJC-1295 exists in two distinct forms with vastly different pharmacokinetics: the DAC version acts for days, while Modified GRF 1-29 without DAC has a half-life of only 30 minutes.
CJC-1295 Overview & Molecular Profile
CJC-1295 is a synthetic GHRH analog built on the first 29 amino acids of GHRH with a Drug Affinity Complex (DAC) lysine modification that enables covalent binding to serum albumin. This albumin binding extends the half-life from minutes to 6–8 days, enabling once-weekly dosing with sustained GH and IGF-1 elevation. First described in a 2006 JCEM study, it exists in two forms: with DAC (long-acting) and without DAC (Modified GRF 1-29; ~30-minute half-life).
Mechanism of Action: Hormonal Signaling & Receptor Binding
CJC-1295 acts on the GHRH receptor in the pituitary gland to stimulate growth hormone release. The DAC modification allows the peptide to bind covalently to serum albumin after injection, protecting it from enzymatic degradation and extending its biological half-life from minutes to days. This results in sustained elevation of GH and IGF-1 levels. The peptide amplifies the natural GH pulsatile release pattern rather than creating artificial spikes.
Research-Observed Effects
Sustained GH Elevation
Research demonstrates that CJC-1295 with DAC produces remarkably prolonged elevation of growth hormone levels lasting 6-8 days following a single subcutaneous injection, fundamentally different from the short-lived pulses produced by other GH-releasing compounds. The Drug Affinity Complex binds covalently to albumin in the bloodstream, protecting the peptide from enzymatic degradation and extending its biological activity dramatically. Studies show 2-10 fold elevations in mean GH levels that persist throughout the week, while importantly maintaining the natural pulsatile secretion pattern rather than creating unnatural constant elevation. This sustained release profile has made CJC-1295 valuable for research into growth hormone replacement strategies, aging-related GH decline, and optimization of GH therapy protocols. The extended half-life also enables study of long-term GH elevation effects without the confounding variable of repeated daily injections.
IGF-1 Increase
Clinical studies demonstrate significant and sustained increases in Insulin-like Growth Factor-1 (IGF-1) levels following CJC-1295 administration, with elevations persisting for days to weeks depending on the dosing protocol. IGF-1, produced primarily by the liver in response to growth hormone, mediates many of GH's anabolic and metabolic effects throughout the body. Research shows dose-dependent IGF-1 increases ranging from 50% to 200% above baseline, with effects on tissue regeneration, protein synthesis, and cellular growth pathways. The sustained IGF-1 elevation profile makes CJC-1295 particularly valuable for studying the effects of chronic IGF-1 exposure on muscle metabolism, bone formation, and age-related tissue decline. Studies have documented maintained IGF-1 elevation for up to 2 weeks following a single CJC-1295 administration in some protocols.
Body Composition Research
Research indicates CJC-1295 may influence body composition through multiple GH and IGF-1 mediated pathways including enhanced lipolysis (fat breakdown), increased lean body mass, and improved protein synthesis in skeletal muscle tissue. Studies have documented potential reductions in visceral adipose tissue (abdominal fat), which is associated with metabolic disease risk, along with improvements in fat-free mass. The peptide has been investigated for obesity research applications, sarcopenia (age-related muscle loss) prevention studies, and metabolic syndrome investigations. Long-term animal studies suggest favorable body composition changes including reduced body fat percentage and increased muscle mass without the water retention sometimes associated with direct GH administration. These findings have implications for research into healthy aging, athletic performance optimization, and metabolic health.
Sleep Quality Studies
Preliminary research suggests CJC-1295 may improve sleep architecture, particularly enhancing slow-wave (deep) sleep phases when natural growth hormone release peaks occur. Studies indicate that optimized GH pulsatility achieved through GHRH analog administration may support the natural relationship between deep sleep and growth hormone secretion. Research has documented improvements in subjective sleep quality measures and potential enhancement of recovery processes associated with quality sleep. These findings have implications for aging research where both sleep quality and GH production naturally decline, as well as for recovery optimization studies in athletic and rehabilitation contexts. The sustained GH elevation may support overnight recovery and tissue repair processes.
Synergistic GHRP Combination
Extensive research demonstrates that CJC-1295 produces synergistic effects when combined with growth hormone releasing peptides such as Ipamorelin or GHRP-6, resulting in substantially greater GH release than either compound alone. This synergy occurs because CJC-1295 acts on GHRH receptors while GHRPs act on ghrelin receptors, activating complementary pathways that amplify pituitary GH secretion. Studies document 2-5 fold greater GH release with combined administration compared to either peptide individually. This combination approach has become a standard research protocol for studying maximized natural GH secretion, optimal body composition effects, and the potential therapeutic applications of enhanced GH/IGF-1 axis activation.
Research Dosing Information
| Route | Dose | Frequency | Notes |
|---|---|---|---|
| Subcutaneous (with DAC) | 30–60 mcg/kg | Once weekly or biweekly | Sustained GH/IGF-1 elevation for 6–8 days |
| Subcutaneous (without DAC) | 100–300 mcg | 2–3× daily | Modified GRF 1-29; t½ ~30 min; creates acute GH pulses |
| Intravenous (with DAC) | 30–60 mcg/kg | As per protocol | Used in clinical PK studies (PMID: 16352683) |
Note: Dosing information is provided for research reference only and is based on published studies using research subjects. This is not a recommendation for any use.
Research Studies & References
Prolonged stimulation of growth hormone and insulin-like growth factor 1 secretion by CJC-1295
Teichman SL, Neale A, et al. (2006). Journal of Clinical Endocrinology & Metabolism
This landmark clinical study established CJC-1295's unique pharmacokinetic profile through comprehensive evaluation in healthy adult volunteers receiving single and multiple dose administrations. Researchers demonstrated that the Drug Affinity Complex modification enabled sustained growth hormone elevation lasting 6-8 days from a single injection, representing a major advancement over native GHRH with its minutes-long half-life. The study documented dose-dependent IGF-1 increases reaching 1.5-3 fold above baseline with effects persisting for up to 2 weeks. Safety analysis revealed excellent tolerability with injection site reactions being the most common adverse effect. The research established CJC-1295 as the first clinically viable long-acting GHRH analog and demonstrated its potential for once-weekly or less frequent dosing in GH replacement research protocols.
CJC-1295 combined with GHRP-6: Synergistic effects on growth hormone secretion
Alba M, Fintini D, et al. (2008). Journal of Endocrinological Investigation
This important combination study evaluated the synergistic effects of CJC-1295 with GHRP-6 on growth hormone secretion patterns in both animal models and preliminary human trials. Researchers demonstrated that co-administration produced significantly greater GH release than either compound alone, with peak GH levels 2-5 times higher than single-agent treatment. The study provided mechanistic insight showing that activation of both GHRH and ghrelin receptor pathways simultaneously amplifies pituitary responsiveness and overcomes negative feedback inhibition. Pharmacokinetic analysis confirmed that the combination maintained CJC-1295's extended duration of action while adding the acute GH pulse characteristic of GHRP administration. These findings established the scientific basis for combination protocols now widely used in GH axis research.
Comparative Research
Explore in-depth research analyses and comparative studies featuring CJC-1295.
Comparative Clinical Analysis
CJC-1295 vs Ipamorelin: GHRH Analog vs GHRP Comparison for Growth Hormone Research
CJC-1295 and Ipamorelin represent two complementary mechanisms for stimulating growth hormone release, which is why they are frequently combined in research settings. CJC-1295, a GHRH (growth hormone ...
Sermorelin vs CJC-1295: GHRH Analog Comparison for Growth Hormone Research
Sermorelin and CJC-1295 are both GHRH analogs that stimulate pituitary GH release through the GHRH receptor, but differ dramatically in pharmacokinetics. Sermorelin is the natural GHRH (1-29) fragment...
Frequently Asked Questions
What is the difference between CJC-1295 with DAC and without DAC?
CJC-1295 with DAC (Drug Affinity Complex) has a lysine modification that covalently binds to serum albumin, extending its biological half-life from minutes to 6–8 days. This allows once-weekly dosing and creates sustained GH/IGF-1 elevation. Without DAC (Modified GRF 1-29), CJC-1295 behaves like native GHRH with a ~30-minute half-life, requiring 2–3 daily injections to maintain effect. Researchers choose between them based on whether sustained elevation or pulsatile GH mimicry is desired.
What does the clinical evidence show for CJC-1295?
A published Phase I/II dose-escalation study in healthy adults (PMID: 16352683; JCEM 2006) found a single CJC-1295 with DAC injection produced dose-dependent GH increases (up to 2–10× baseline) and IGF-1 increases (up to 1.5–3× baseline) lasting 6–7 days in 66 subjects. This is one of the few GHRH analog peptides with published human clinical PK/PD data. Extended efficacy trials or regulatory approval have not followed.
How does CJC-1295 compare to Sermorelin?
Both are GHRH analogs activating the same pituitary GHRHR, but with different pharmacokinetics. Sermorelin uses only the first 29 amino acids of GHRH without stability modifications, giving it a ~10-minute half-life requiring nightly injection to leverage peak nocturnal GH release. CJC-1295 with DAC enables weekly dosing. Sermorelin has more published human data (FDA-approved historically for pediatric GH deficiency) but shorter duration. CJC-1295 offers convenience but carries concerns about sustained GHRHR stimulation.
Why is CJC-1295 often combined with Ipamorelin?
CJC-1295 and Ipamorelin activate complementary receptor pathways. CJC-1295 acts on the GHRH receptor, while Ipamorelin acts on the ghrelin receptor (GHSR-1a)—both on the same pituitary somatotroph cells. These pathways synergize: activation of one primes the cell to respond more strongly to the other. The combination produces GH release 2–5× greater than either compound alone, making it a common protocol in GH axis research.
Does CJC-1295 suppress natural GHRH secretion?
Sustained GHRHR activation by CJC-1295 with DAC could theoretically cause receptor downregulation or feedback suppression of endogenous GHRH release. The 2006 clinical study noted this theoretical concern but did not observe pituitary desensitization within its study window. Whether long-term use causes clinically meaningful GH axis suppression remains uncharacterized in published research.
What is the half-life of CJC-1295 without DAC?
CJC-1295 without DAC (Modified GRF 1-29) has a plasma half-life of approximately 30 minutes—far shorter than the DAC version's 6–8 days. This requires 2–3 daily injections to maintain GH stimulation. The benefit is that it creates discrete GH pulses more closely mimicking physiological pulsatility, which may be preferred in research models specifically studying GH pulsatility axis dynamics.
Is CJC-1295 approved for any medical use?
CJC-1295 is not approved for any medical use by any regulatory agency as of 2026. It is an investigational research peptide and should not be confused with Sermorelin, which was historically FDA-approved for pediatric GH deficiency. All CJC-1295 available commercially is for research use only and is not intended for clinical human administration.
What are the storage and stability requirements for CJC-1295?
Lyophilized CJC-1295 is stable at -20°C for extended periods. Once reconstituted in bacteriostatic water, it should be stored at 2–8°C and used within 2–4 weeks. The DAC modification provides additional stability compared to unmodified GHRH. Researchers should avoid repeated freeze-thaw cycles, which degrade both the peptide structure and the DAC albumin-binding moiety.
Ipamorelin
C38H49N9O5
Ipamorelin is a selective growth hormone secretagogue and ghrelin receptor agonist. It stimulates the release of growth hormone from the pituitary gland without significantly affecting cortisol or prolactin levels.
GHRP-6
C46H56N12O6
GHRP-6 is a synthetic hexapeptide that stimulates growth hormone release through the ghrelin receptor. It was one of the first growth hormone releasing peptides developed.