What Is CJC-1295? Definition and What Research Reports
CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH) built from the first 29 amino acids of human GHRH, with substitutions and a linker that lets it bind albumin in the blood. That binding extends its presence from minutes to days. Published studies in rats, knockout mice and healthy adults reported sustained rises in growth hormone and IGF-1 after single injections. It is not an approved medicine, and much of the recent literature concerns detection and misuse.
Plain-language definition
CJC-1295 is a laboratory-made peptide designed to mimic growth hormone-releasing hormone (GHRH), the natural signal the hypothalamus sends to the pituitary gland telling it to release growth hormone (GH). Natural GHRH breaks down within minutes. CJC-1295 was engineered to survive far longer by chemically latching onto albumin, the most abundant protein in blood, so a single injection can keep signalling for days rather than minutes. It is an investigational compound rather than an approved medicine, and most of what is publicly known about it comes from a small cluster of animal studies, early-phase human trials published in 2005–2009, and later anti-doping and forensic chemistry work. This page is for educational purposes only and is not medical advice; consult a licensed physician with questions about any substance or health condition.
What CJC-1295 is in biochemical terms
CJC-1295 is built on hGRF(1-29), the biologically active fragment made up of the first 29 amino acids of human growth hormone-releasing factor. Four amino acid substitutions were introduced to resist enzymatic degradation, and a reactive maleimido linker — often described in the literature as Drug Affinity Complex (DAC) technology — was attached so the molecule forms a covalent bond with circulating albumin after injection. The albumin conjugate then acts as a slow-release depot that continues to present the GHRH sequence to pituitary receptors.
The foundational chemistry paper on this design described hGRF(1-29)-albumin bioconjugates activating the GRF receptor on the anterior pituitary in rats and identified CJC-1295 as the long-lasting candidate emerging from that series (PMID 15817669). In other words, CJC-1295 is not a growth hormone and does not act on GH receptors; it acts one step upstream, on the GHRH receptor, and the pituitary decides how much GH to release.
What the published literature reports
Animal studies
In rats, researchers reported that the albumin-bound GRF conjugates retained receptor activity at the anterior pituitary and produced a far longer duration of action than unmodified hGRF(1-29) (PMID 15817669). A separate study in GHRH knockout mice — animals that cannot make their own GHRH and therefore grow poorly — reported that once-daily administration of CJC-1295 normalized growth in that model (PMID 16822960). Those two papers together established the proof of concept that a long-acting GHRH analog could restore or amplify GH-axis signalling in vivo.
Human trials
The most frequently cited human data come from a randomized, double-blind, placebo-controlled study in healthy adults. The study administered single subcutaneous doses across a range of 30 to 250 µg/kg and reported dose-dependent increases in GH of roughly two- to ten-fold for several days, with IGF-1 rising approximately 1.5- to 3-fold and remaining elevated for about 9 to 11 days; the estimated half-life of CJC-1295 was reported in the range of 5.8 to 8.1 days, and repeated administration at weekly or biweekly intervals sustained IGF-1 elevations (PMID 16352683).
A related question was whether continuous GHRH-receptor stimulation would flatten the body's normal pulsatile GH rhythm. Researchers examined this directly and reported that pulsatile GH secretion persisted during continuous stimulation by CJC-1295, with mean GH concentrations increased several-fold while the underlying pulse pattern was preserved (PMID 17018654). A later analysis of samples from normal adult subjects reported that activation of the GH/IGF-1 axis by CJC-1295 was accompanied by measurable changes in the serum protein profile (PMID 19386527), which was framed as a possible route toward biomarker-based detection.
Detection, forensics and misuse literature
Most CJC-1295 publications after 2009 are not clinical. Analytical chemists reported identifying CJC-1295 as the active ingredient in an unknown, unlabelled pharmaceutical preparation, illustrating that the peptide circulated outside regulated supply chains (PMID 21204297). In equine sport, two methods were published for detecting the compound in horse plasma: an LC-MS/MS confirmation method for CJC-1295 abuse (PMID 30938069) and an immuno-polymerase chain reaction screen able to detect CJC-1295 and other GHRH analogs (PMID 30489688). A qualitative netnography examined how women discussed synthetic GH-axis compounds including CJC-1295 in online communities, documenting informal information-sharing rather than clinical outcomes (PMID 26771670).
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Try it freeAdverse Events: What Studies Report
The published human safety record for CJC-1295 is thin because the trials were small and short. In the randomized placebo-controlled trial in healthy adults, researchers reported that the compound was generally well tolerated across the dose range studied, with no serious adverse events described in that report (PMID 16352683). The companion pulsatility study similarly did not report tolerability problems that halted the protocol (PMID 17018654).
Those findings describe short-term, supervised administration in screened healthy volunteers. No published long-term safety data, no cancer-risk data and no data in older adults, children or people with chronic disease appear in the verified literature above. The forensic papers add a separate category of risk: material identified outside regulated manufacturing had unknown purity and labelling (PMID 21204297).
How the term is used — and where it is misused
Three recurring sources of confusion appear in non-academic writing about CJC-1295:
- "CJC-1295 no DAC." The DAC linker is the defining feature of CJC-1295 in the primary literature (PMID 15817669). A modified GRF(1-29) peptide without that linker is a different molecule with a different duration profile, and applying the CJC-1295 name to it blurs which published data can reasonably be referenced.
- Calling it a "growth hormone" or a "GH peptide." CJC-1295 is a GHRH-receptor agonist, not GH itself. The distinction matters because the pituitary remains an intermediate step, which is why pulsatility persisted in the human study (PMID 17018654).
- Treating early-phase endocrine trial data as outcome data. The human studies measured hormone concentrations and protein profiles (PMID 16352683, PMID 19386527). They did not measure body composition, athletic performance, recovery or longevity endpoints.
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Get the appRelated terms
| Term | What it refers to |
|---|---|
| GHRH / GRF | The natural hypothalamic hormone that stimulates pituitary GH release; CJC-1295 is an analog of its 1-29 fragment. |
| hGRF(1-29) | The 29-amino-acid active fragment of human GHRH that forms the backbone of CJC-1295. |
| DAC (Drug Affinity Complex) | The linker chemistry that lets the peptide bind albumin, extending its circulating lifetime. |
| Sermorelin | An unmodified hGRF(1-29) peptide; short-acting by comparison. |
| Tesamorelin | A separate GHRH analog that reached FDA approval for HIV-associated lipodystrophy. |
| GH secretagogues (e.g. ipamorelin, GHRP-class peptides) | Compounds acting at the ghrelin/GHS receptor, a different receptor from the GHRH receptor CJC-1295 targets. |
| IGF-1 | Insulin-like growth factor 1, the downstream marker measured in the CJC-1295 human trials. |
Regulatory and research status
CJC-1295 has no marketing approval as a human medicine in the United States, and material offered under the name is typically labelled for research use only. Its appearance in equine anti-doping method development (PMID 30938069, PMID 30489688) reflects that regulators in sport treat GHRH analogs as performance-relevant substances requiring surveillance. Nothing on this page is legal advice.
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Start learning freeLimits of the evidence
The human CJC-1295 literature consists of a small number of early-phase pharmacology studies published in 2006 and 2009, conducted in healthy volunteers and reporting hormone kinetics rather than clinical outcomes (PMID 16352683, PMID 17018654, PMID 19386527). The animal work established mechanism and growth restoration in a genetically GHRH-deficient model (PMID 16822960). Readers evaluating claims about CJC-1295 can reasonably ask which of these papers a given claim traces back to, and whether the endpoint being claimed was actually measured.
References
- Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog (Endocrinology, 2005)
- Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults (The Journal of Clinical Endocrinology and Metabolism, 2006)
- Once-daily administration of CJC-1295, a long-acting growth hormone-releasing hormone (GHRH) analog, normalizes growth in the GHRH knockout mouse (American Journal of Physiology. Endocrinology and Metabolism, 2006)
- Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog (The Journal of Clinical Endocrinology and Metabolism, 2006)
- Activation of the GH/IGF-1 axis by CJC-1295, a long-acting GHRH analog, results in serum protein profile changes in normal adult subjects (Growth Hormone & IGF Research, 2009)
- Identification of CJC-1295, a growth-hormone-releasing peptide, in an unknown pharmaceutical preparation (Drug Testing and Analysis, 2010)
- Netnography of Female Use of the Synthetic Growth Hormone CJC-1295: Pulses and Potions (Substance Use & Misuse, 2016)
- An immuno polymerase chain reaction screen for the detection of CJC-1295 and other growth-hormone-releasing hormone analogs in equine plasma (Drug Testing and Analysis, 2019)
- A method for confirming CJC-1295 abuse in equine plasma samples by LC-MS/MS (Drug Testing and Analysis, 2019)
Frequently asked questions
What is CJC-1295 in one sentence?▾
CJC-1295 is a synthetic analog of growth hormone-releasing hormone, based on the hGRF(1-29) fragment and modified with a linker that binds albumin so the molecule persists in circulation for days. The original chemistry paper identified it as a long-lasting GRF analog that activated the GRF receptor on the anterior pituitary in rats (PMID 15817669).
What did human studies report about CJC-1295?▾
A randomized, placebo-controlled study in healthy adults administered single subcutaneous doses of 30 to 250 µg/kg and reported roughly two- to ten-fold GH increases and about 1.5- to 3-fold IGF-1 increases lasting around 9 to 11 days, with a half-life reported between 5.8 and 8.1 days (PMID 16352683).
Does CJC-1295 suppress the body's natural GH pulses?▾
Researchers specifically tested this question and reported that pulsatile GH secretion persisted during continuous stimulation by CJC-1295 in healthy adults, with mean GH concentrations rising several-fold while the underlying pulse pattern remained (PMID 17018654). That study measured hormone dynamics only and did not assess long-term physiological consequences.
What is the difference between CJC-1295 and "CJC-1295 no DAC"?▾
The albumin-binding Drug Affinity Complex linker is the defining feature of CJC-1295 in the primary literature (PMID 15817669). A modified GRF(1-29) peptide lacking that linker is chemically different and has a different duration profile, so human data generated with CJC-1295 (PMID 16352683) do not automatically describe the non-DAC version.
What adverse events have studies reported?▾
Published human data are limited. The randomized placebo-controlled trial in healthy adults reported that CJC-1295 was generally well tolerated across the doses studied, with no serious adverse events described (PMID 16352683), and the pulsatility study reported no tolerability issues that stopped the protocol (PMID 17018654). No long-term safety data appear in this literature.
Why does CJC-1295 appear in anti-doping research?▾
Because GHRH analogs are treated as performance-relevant in sport, analysts developed detection tools: an LC-MS/MS confirmation method for CJC-1295 in equine plasma (PMID 30938069) and an immuno-PCR screen covering CJC-1295 and other GHRH analogs (PMID 30489688). Serum protein profile changes after CJC-1295 have also been studied as a possible detection route (PMID 19386527).
Is CJC-1295 an approved medicine?▾
No approved human product carries CJC-1295 as its active ingredient; material circulating under the name is typically designated research use only. Forensic chemists reported identifying CJC-1295 as the ingredient of an unlabelled pharmaceutical preparation of unknown origin (PMID 21204297), and online discussion communities have been studied qualitatively rather than clinically (PMID 26771670).
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References
This page summarises published research for education — it is not medical advice, and nothing here is a recommendation to use, purchase, or dose any substance. Study parameters described are what researchers reported, not instructions. Consult a qualified clinician before any health decision.