CJC-1295 (DAC): A Literature Course in Six Modules

About this course

This course organises the published literature on CJC-1295 into six modules: what the compound is, the mechanism described in animal and human work, the outcomes reported study by study, the adverse events that appear in print, the pharmacokinetic values that exist, and the regulatory position of the molecule. Every module closes with an explicit statement of what the cited evidence cannot support. Nothing here is a protocol, a recommendation, or a claim about what any individual might experience. This page is for educational purposes only and is not medical advice; consult a licensed physician about any health question or any compound.

Module 1: What CJC-1295 Is and How It Has Been Studied

Definition and class

CJC-1295 belongs to the class of growth hormone-releasing hormone (GHRH) analogs, also described in the literature as growth hormone secretagogues acting at the pituitary. Its peptide backbone corresponds to the biologically active 1-29 fragment of human growth hormone-releasing factor, hGRF(1-29), with amino acid substitutions intended to resist enzymatic degradation, plus a chemical linker known as a drug affinity complex (DAC). Researchers described the underlying chemistry in a rat study of hGRF(1-29)-albumin bioconjugates that identified CJC-1295 as a long-lasting GRF analog able to activate the GRF receptor on the anterior pituitary (PMID 15817669).

Origin and development context

The molecule emerged from a bioconjugation programme in which a reactive maleimide group was attached to a modified GRF peptide so that it would bind covalently to circulating albumin after administration; the study reported that these albumin bioconjugates retained the ability to activate the pituitary GRF receptor in rats (PMID 15817669). Development then moved to disease-model and early human work. A separate paper reported that once-daily administration of CJC-1295 normalized growth in the GHRH knockout mouse, a model in which endogenous GHRH signalling is absent (PMID 16822960). Human data come from a small number of early-phase studies in healthy adults published in 2006 and a proteomic analysis published in 2009.

Forms and naming

Two naming conventions circulate. "CJC-1295 with DAC" refers to the albumin-binding conjugate that the published pharmacology describes (PMID 15817669). "CJC-1295 without DAC" is a label commonly applied to modified GRF(1-29) — the same peptide sequence without the albumin-binding linker — and that shorter-acting form is not the molecule evaluated in the human trials cited throughout this course. Identity is not trivial in unregulated supply: analytical chemists reported the identification of CJC-1295 in an unknown pharmaceutical preparation submitted for testing, a case study in products whose contents were not declared (PMID 21204297).

Limits of the evidence in Module 1

• The published human literature on CJC-1295 is small, early-phase, and concentrated in healthy adult volunteers.
• No verified study in this course compared the DAC form directly against the non-DAC form in humans.
• Chemical identity in commercially circulating material has been questioned in at least one analytical case report (PMID 21204297).

Module 2: Mechanism as Described in the Literature

Receptor-level action

The mechanism described in print is indirect: the analog is reported to act at the GHRH (GRF) receptor on anterior pituitary somatotrophs rather than supplying growth hormone itself. The rat bioconjugate study reported that hGRF(1-29)-albumin conjugates activated the GRF receptor on the anterior pituitary, establishing that albumin attachment did not abolish receptor activity (PMID 15817669). Downstream, pituitary growth hormone release drives hepatic insulin-like growth factor I (IGF-I) production, and the human study reported prolonged stimulation of both GH and IGF-I secretion in healthy adults (PMID 16352683).

Why the DAC changes duration

The design rationale in the literature is that covalent binding to albumin extends circulating residence far beyond that of native GHRH, which is cleared rapidly. Researchers identified CJC-1295 as a long-lasting GRF analog on the basis of this bioconjugate approach in rats (PMID 15817669), and the human trial reported a terminal half-life of 5.8 to 8.1 days in healthy adults (PMID 16352683).

Continuous stimulation versus pulsatility

A recurring mechanistic question is whether a long-acting GHRH analog flattens the normal pulsatile pattern of GH secretion. In a dedicated human study using frequent blood sampling after subcutaneous administration, researchers reported that pulsatile GH secretion persisted during continuous stimulation by CJC-1295, with pulse amplitude increased while pulse frequency was not abolished (PMID 17018654). A separate analysis of the same population reported that activation of the GH/IGF-1 axis by CJC-1295 was accompanied by measurable changes in serum protein profiles in normal adult subjects (PMID 19386527).

Limits of the evidence in Module 2

• Mechanistic descriptions rest on receptor pharmacology in rats and on hormone measurements in healthy volunteers, not on tissue-level outcomes in patients.
• The serum protein changes reported were biomarker observations; the study did not establish clinical meaning for them (PMID 19386527).
• Preserved pulsatility was observed over short sampling windows and does not describe what happens over months of exposure (PMID 17018654).

Module 3: Reported Outcomes, Study by Study

Animal work

The foundational rat study reported that hGRF(1-29)-albumin bioconjugates activated the pituitary GRF receptor and identified CJC-1295 as the long-lasting candidate from that series (PMID 15817669). In a disease model, once-daily administration of CJC-1295 normalized growth in GHRH knockout mice, an endpoint of body growth in animals that cannot produce endogenous GHRH (PMID 16822960).

Human endocrine endpoints

The principal human dataset comes from placebo-controlled work in healthy adults, where the study reported that single subcutaneous doses of 30, 60, 125 and 250 µg/kg produced dose-dependent increases in mean growth hormone concentrations of approximately 2- to 10-fold for six days or more (PMID 16352683). In the same trial programme, researchers reported that IGF-I concentrations rose approximately 1.5- to 3-fold and remained elevated for 9 to 11 days after dosing (PMID 16352683). A companion study reported that GH secretion remained pulsatile during this sustained stimulation rather than becoming flat and continuous (PMID 17018654).

Biomarker and observational work

A 2009 analysis reported that activation of the GH/IGF-1 axis by CJC-1295 produced changes in the serum protein profile of normal adult subjects, framed as exploratory proteomics rather than an efficacy endpoint (PMID 19386527). Outside clinical research, a qualitative netnographic study analysed online discussion by women describing synthetic growth hormone and CJC-1295 use, reporting themes around self-directed practices and perceived effects derived from forum text rather than measurement (PMID 26771670).

Analytical and anti-doping literature

Two equine studies reported analytical methods rather than physiological outcomes: one described an LC-MS/MS method for confirming CJC-1295 abuse in equine plasma samples (PMID 30938069), and another described an immuno polymerase chain reaction screen for detecting CJC-1295 and other GHRH analogs in equine plasma (PMID 30489688).

Limits of the evidence in Module 3

• Reported endpoints in humans were hormone concentrations and biomarkers, not body composition, strength, sleep, injury recovery or longevity outcomes.
• Animal growth normalization occurred in a knockout model of GHRH deficiency and does not transfer to hormonally normal adults (PMID 16822960).
• Forum-based findings describe what people wrote online, not verified exposures or verified effects (PMID 26771670).

Module 4: CJC-1295 Side Effects: What Studies Report

Tolerability in controlled human trials

In the placebo-controlled human trials in healthy adults, the study concluded that CJC-1295 was safe and relatively well tolerated, with that conclusion tied particularly to the lower doses of 30 and 60 µg/kg among the single doses tested up to 250 µg/kg (PMID 16352683). The parallel pulsatility study reported hormonal measurements after subcutaneous administration in healthy volunteers without describing a distinct adverse-event signal in its published scope (PMID 17018654).

Biological changes of uncertain significance

Researchers reported that activation of the GH/IGF-1 axis by CJC-1295 altered serum protein profiles in normal adult subjects, a finding presented as a biological consequence of axis stimulation rather than as a benefit or a harm (PMID 19386527). Sustained elevation of IGF-I for 9 to 11 days after a single dose was also reported in the human trial, which is relevant context for any discussion of prolonged axis stimulation (PMID 16352683).

Risks described outside clinical settings

Two published observations bear on non-clinical exposure. The netnographic study reported that women discussed obtaining and using synthetic growth hormone and CJC-1295 through informal channels, with information exchanged peer-to-peer (PMID 26771670). Separately, analysts reported identifying CJC-1295 in an unknown pharmaceutical preparation, illustrating that material circulating outside regulated manufacture may not be labelled accurately (PMID 21204297).

Limits of the evidence in Module 4

• Adverse-event data derive from small, short early-phase trials in healthy adults; rare or delayed events would not be detectable at that scale (PMID 16352683).
• No verified study in this course followed participants for months or years, and none evaluated cancer risk, glucose metabolism over time, or cardiovascular endpoints.
• No verified study assessed safety in pregnancy, in adolescents, or in people with pituitary, hepatic or renal disease.

Module 5: Pharmacokinetics Where Data Exist

The human trial reported a terminal half-life of 5.8 to 8.1 days after subcutaneous administration in healthy adults, which is the principal published pharmacokinetic parameter for the DAC form (PMID 16352683). Pharmacodynamic duration followed the same pattern: the study reported mean GH elevation persisting for six days or longer and IGF-I elevation persisting 9 to 11 days after a single dose (PMID 16352683). The mechanistic basis for this duration, albumin bioconjugation, was described in the rat study that identified CJC-1295 as a long-lasting GRF analog (PMID 15817669).

Detection science provides indirect pharmacokinetic context in animals. Researchers reported an LC-MS/MS confirmation method for CJC-1295 in equine plasma (PMID 30938069) and an immuno-PCR screening assay capable of detecting CJC-1295 and related GHRH analogs in equine plasma (PMID 30489688). Those methods were developed for racing integrity testing, and their sensitivity thresholds are analytical rather than clinical parameters.

Limits of the evidence in Module 5

• Published human pharmacokinetics come from healthy volunteers in early-phase studies; no verified data describe accumulation with long-term repeated exposure.
• Equine assay work describes detectability in horses, not human clearance (PMID 30938069).
• No verified study in this course reported bioavailability comparisons between administration routes.

Module 6: Regulatory Status, Stated Factually

Approval status

CJC-1295 has not been approved as a medicine by the U.S. Food and Drug Administration or by the European Medicines Agency for any indication. It did not complete the late-phase clinical development that approval requires. Other molecules that act on the same axis have been approved: tesamorelin, a stabilised GHRH analog, holds U.S. approval for a specific HIV-associated lipodystrophy indication, and sermorelin, the unmodified GRF(1-29) peptide, was previously marketed in the United States before being withdrawn from the market for commercial reasons.

Research-use-only material and compounding

Material labelled "research use only" is not manufactured to pharmaceutical standards and is not intended for human administration; the label denotes laboratory chemical status rather than a quality or safety certification. The FDA has evaluated peptides nominated for use in compounded preparations under section 503A of the Federal Food, Drug, and Cosmetic Act and placed several — including CJC-1295 — in the category of substances for which significant safety risks were identified, which limits their lawful use in compounding. The analytical identification of CJC-1295 in an unknown pharmaceutical preparation underlines why regulators treat unverified peptide products as an identity and purity problem (PMID 21204297).

Sport and animal competition

GHRH analogs are prohibited in human sport under the World Anti-Doping Agency's hormone and metabolic modulator provisions, at all times, in and out of competition. In equine racing, dedicated detection chemistry has been published: researchers reported both a confirmatory LC-MS/MS method (PMID 30938069) and an immuno-PCR screening approach for GHRH analogs including CJC-1295 (PMID 30489688). Regulatory descriptions here are factual summaries and not legal advice; rules differ by jurisdiction and change over time.

Limits of the evidence in Module 6

• Regulatory categorisation reflects administrative evaluation of available safety data, not a finding from any single study listed here.
• Status varies by country and by sporting body, and the verified literature does not adjudicate legality anywhere.

What the Studies Did Not Test

Across the verified literature, several questions remain unaddressed. No cited study measured fat mass, lean mass, strength, athletic performance, wound healing, sleep architecture, cognition or quality of life as endpoints. No cited study enrolled people with growth hormone deficiency, older adults specifically, or clinical populations with metabolic disease. No cited study ran longer than the short exposure windows of early-phase design, so durability, tolerance to repeated stimulation, and long-term oncologic or metabolic safety were not evaluated. No cited study compared CJC-1295 against recombinant growth hormone or against other secretagogues on clinical outcomes. And no cited study evaluated the non-DAC modified GRF(1-29) form in humans. The published record establishes that the molecule raises GH and IGF-I for days in healthy adults (PMID 16352683) while preserving pulsatility over the sampling periods studied (PMID 17018654); what those hormonal changes translate into over time was not the question these studies asked.

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)