What Is CJC-1295? Mechanism and Evidence
TL;DR: CJC-1295 is a synthetic analog of growth-hormone-releasing hormone (GHRH), the endogenous hypothalamic peptide that signals the anterior pituitary to secrete growth hormone (GH). Its defining feature is the Drug Affinity Complex (DAC) — a maleimido group that covalently binds serum albumin in vivo, extending plasma half-life from the minutes seen with native GHRH to an estimated 5–8 days. Published human pharmacokinetic data (Teichman et al., 2006; Ionescu & Frohman, 2006) document sustained, dose-dependent GH and IGF-1 elevation with preserved pulsatility. CJC-1295 is not FDA approved, and is prohibited by WADA under Section S2. It is often studied alongside ghrelin-receptor agonists such as ipamorelin.
Research-Use Disclaimer: This article is for educational and research reference purposes only. CJC-1295 is a research compound, not approved by the FDA for human use. This content does not constitute medical advice, does not recommend or endorse human administration of any compound, and does not describe protocols for personal use. All study findings described below refer to published preclinical and clinical pharmacokinetic research. For adults 18+ with a research interest only.
What Is CJC-1295? Definition and Structural Origins
CJC-1295 is a synthetic growth-hormone-releasing hormone (GHRH) analog — a modified version of the first 29 amino acids of human GHRH (hGRF 1-29) that retains GHRH receptor agonist activity while addressing the central pharmacokinetic limitation of the native peptide: an endogenous half-life of less than 10 minutes in circulation, due to rapid cleavage by dipeptidyl peptidase IV (DPP-IV).
The compound was identified and characterized by ConjuChem Inc. A 2005 paper by Jetté et al. in Endocrinology described the synthesis of three maleimido derivatives of hGRF(1-29) and their bioconjugation to human serum albumin. The compound selected for further development — designated CJC-1295 — is a tetrasubstituted form of hGRF(1-29) with an added Nε-3-maleimidopropionamide derivative of lysine at the C-terminus. This modification allowed in vivo covalent binding to the free thiol group on Cys34 of endogenous serum albumin, fundamentally changing the compound's pharmacokinetic profile.
In the Legendary Labz Peptide Research Guide, CJC-1295 is categorized within the GH Axis & Secretagogues cluster. Because human pharmacokinetic data from randomized controlled trials exists, but therapeutic indication studies in clinical populations are limited, it is assigned an evidence tier of Tier 2: human pharmacokinetic and mechanistic data; limited therapeutic RCT evidence.
What Is the DAC vs. Non-DAC Distinction?
CJC-1295 appears under two distinct labels in the research literature, and the difference is pharmacokinetically significant:
- CJC-1295 with DAC (Drug Affinity Complex)
- The original compound developed by ConjuChem. The DAC refers to the maleimido reactive group that covalently and permanently bonds to serum albumin after injection. Albumin has a plasma half-life of approximately 19 days in humans, and the resulting CJC-1295–albumin conjugate inherits a substantially extended duration of action. Published human studies measured a CJC-1295 plasma half-life of 5.8–8.1 days.
- CJC-1295 without DAC (Modified GRF 1-29 / mod GRF 1-29)
- A truncated descriptor for the modified hGRF(1-29) backbone — which retains the four amino acid substitutions that confer DPP-IV resistance and receptor stability — but without the albumin-binding maleimido group. Without the DAC, the compound's half-life returns to the range of approximately 30 minutes. Mod GRF 1-29 and CJC-1295 with DAC are therefore distinct compounds with materially different pharmacokinetic profiles, despite sharing structural overlap. Researchers should not conflate findings from one with the other.
How Does CJC-1295 Work? The GHRH Receptor Mechanism
CJC-1295 acts as a GHRH receptor (GHRHR) agonist. The GHRHR is a G protein-coupled receptor expressed on somatotroph cells in the anterior pituitary gland. When GHRH (or an analog such as CJC-1295) binds the GHRHR, it activates the adenylyl cyclase / cAMP / protein kinase A signaling cascade, which drives both the synthesis and pulsatile secretion of growth hormone (GH) from somatotrophs.
GH, once released into systemic circulation, acts on peripheral tissues — most prominently the liver — to stimulate secretion of insulin-like growth factor 1 (IGF-1), the primary mediator of GH's anabolic and metabolic effects. CJC-1295 operates upstream of GH, acting at the hypothalamic-pituitary axis rather than directly at GH target tissues.
Does the albumin-binding mechanism preserve physiological activity?
A key mechanistic question in the pharmacology literature is whether covalent albumin conjugation impairs receptor binding. The 2005 Jetté et al. study in Endocrinology demonstrated that the CJC-1295–albumin conjugate remained bioactive in a GH secretion assay using cultured rat anterior pituitary cells, and showed a 4-fold increase in GH area under the curve over a 2-hour period compared with native hGRF(1-29) in rat models. The albumin molecule is proposed to act as a circulating reservoir, slowly releasing the active peptide or allowing receptor engagement while still conjugated.
What Does the Published Human Evidence Show?
CJC-1295 is notable in the research peptide landscape for having published human pharmacokinetic data from randomized, placebo-controlled trials — a level of evidence not available for most research peptides. The primary human data comes from two studies published in the Journal of Clinical Endocrinology and Metabolism in 2006.
Teichman et al. (2006) — pharmacokinetics and GH/IGF-1 response in healthy adults
Teichman et al. conducted two randomized, double-blind, placebo-controlled, ascending-dose trials in healthy subjects aged 21–61 years. The published findings documented that after a single subcutaneous injection of CJC-1295, mean plasma GH concentrations increased 2- to 10-fold for 6 or more days, and mean plasma IGF-I concentrations rose 1.5- to 3-fold for 9–11 days. The estimated plasma half-life of CJC-1295 was 5.8–8.1 days. After multiple doses, mean IGF-1 levels remained above baseline for up to 28 days. No serious adverse reactions were reported. The authors noted the data supported the "potential utility of CJC-1295 as a therapeutic agent."
Ionescu & Frohman (2006) — pulsatile GH secretion preserved
A second human study by Ionescu and Frohman assessed GH pulsatility via 20-minute blood sampling during an overnight 12-hour period in healthy men (ages 20–40) before and one week after CJC-1295 injection. The study found that GH secretory pulse frequency and magnitude were unaltered, while trough GH levels increased 7.5-fold and overall mean GH and IGF-I levels rose approximately 46% and 45%, respectively. The preservation of pulsatility despite continuous GHRH receptor stimulation was noted as a potentially important physiological characteristic of the compound's mechanism.
Preclinical evidence: GHRH knockout mouse model
A 2006 study by Alba et al. at Johns Hopkins University, published in the American Journal of Physiology — Endocrinology and Metabolism, examined CJC-1295 in mice with ablated GHRH gene expression (GHRH knockout mice) — animals that fail to achieve normal growth due to absent endogenous GHRH signaling. The study found that once-daily administration of CJC-1295 normalized body weight, body length, and femur and tibia length in GHRHKO mice, and increased pituitary GH mRNA, suggesting somatotroph proliferation. This preclinical model demonstrates the compound's activity at the GHRH receptor axis but should not be interpreted as evidence for human therapeutic outcomes.
CJC-1295 and Ghrelin-Receptor Agonists: Why They Are Studied Together
In the research literature, CJC-1295 (a GHRH receptor agonist) is frequently examined alongside ghrelin-receptor agonists — compounds also known as GH secretagogues (GHS) or GH-releasing peptides (GHRPs) — such as ipamorelin. This pairing reflects the dual-pathway architecture of GH release from the pituitary: the GHRH/GHRHR axis and the ghrelin/GHS-R axis are complementary stimulatory inputs. A 2001 study by Ahnfelt-Rønne et al. in Endocrine characterized the interplay between these pathways, noting that GHRP-mediated GH release in rodents was substantially attenuated by resection of the GI tract — the site of ghrelin synthesis — while GHRH-mediated release was unaffected, suggesting the two pathways act through mechanistically distinct but synergistic routes. The co-administration of a GHRH analog and a ghrelin-receptor agonist is studied as a means of examining additive stimulation of both axes simultaneously. This is a research-literature observation; it does not constitute a protocol recommendation for human use.
CJC-1295 Detection in Anti-Doping Research
Given WADA's prohibition, a body of analytical chemistry research has focused on developing detection methods for CJC-1295 in biological samples. A 2019 validation study by Timms et al. in Drug Testing and Analysis, conducted at Racing Analytical Services Ltd in Australia, described a confirmed LC-MS/MS method for CJC-1295 detection in equine plasma. The study noted that CJC-1295–protein conjugates have a much greater half-life compared to the unconjugated peptide and are capable of stimulating GH production for more than six days in humans after a single administration. The method achieved detection limits as low as 180 pg/mL in 1 mL of plasma. This body of work, while developed for equine anti-doping applications, independently corroborates the albumin-binding pharmacokinetics documented in human studies.
What Is CJC-1295's Evidence Summary?
| Evidence Level | Status for CJC-1295 (as of 2026) |
|---|---|
| Human randomized controlled trials (pharmacokinetics) | Yes — two published RCTs (Teichman et al. 2006; Ionescu & Frohman 2006) in healthy adults documenting half-life, GH, and IGF-1 responses |
| Human therapeutic efficacy trials (clinical populations) | Not available for CJC-1295 specifically; GHRH analogs as a class have been studied in GH-deficiency-adjacent populations but not in approved indications for this compound |
| Preclinical animal model studies | Present — GH axis activity confirmed in rodent models including GHRH knockout; growth normalization documented (Alba et al. 2006) |
| Mechanistic / in vitro evidence | Albumin-binding mechanism confirmed; GHRHR bioactivity confirmed in cultured anterior pituitary cells (Jetté et al. 2005) |
| FDA approval status | Not approved for any human use |
| WADA status | Prohibited — Section S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics) |
Honest evidence assessment: CJC-1295 has more published human data than the majority of research peptides — the Teichman et al. and Ionescu & Frohman studies are genuine randomized controlled trials in healthy subjects. However, these trials measured pharmacokinetic parameters and GH/IGF-1 secretory responses; they were not designed or powered to establish therapeutic efficacy or safety in clinical populations. The compound's mechanism is well-characterized at the receptor level, but the downstream effects of sustained GH axis stimulation in diverse human populations — including long-term safety — are not documented by current published evidence. This is a compound with a documented pharmacological mechanism and human PK data, but without the clinical trial base required to characterize therapeutic risk-benefit in any patient population.
What Is CJC-1295's Regulatory Status?
FDA (United States)
CJC-1295 is not approved by the U.S. Food and Drug Administration as a drug or biologic. It has no authorized therapeutic indication and no approved human dosing protocol. It is not available as a dietary supplement ingredient. Researchers should consult current FDA guidance directly for the most current regulatory standing of GHRH analog compounds.
WADA (World Anti-Doping Agency)
CJC-1295 is prohibited under Section S2: Peptide Hormones, Growth Factors, Related Substances and Mimetics of the WADA Prohibited List. Section S2 covers releasing factors and their analogs that stimulate secretion of prohibited hormones including growth hormone. The prohibition applies in-competition and out-of-competition for all athletes subject to WADA rules. Analytical detection methods for CJC-1295 in plasma have been published and validated (Timms et al. 2019).
Frequently Asked Questions About CJC-1295
What is CJC-1295?
CJC-1295 is a synthetic GHRH analog — a modified version of the first 29 amino acids of human growth-hormone-releasing hormone — engineered with a maleimido group (the Drug Affinity Complex, or DAC) that covalently binds serum albumin in vivo. This albumin binding extends the compound's plasma half-life from the minutes characteristic of native GHRH to approximately 5–8 days in human subjects. CJC-1295 acts as a GHRH receptor agonist, stimulating pituitary GH and downstream IGF-1 secretion. It is not FDA approved and is prohibited by WADA.
What is the difference between CJC-1295 with DAC and mod GRF 1-29?
CJC-1295 "with DAC" contains the albumin-binding maleimido group that extends its half-life to 5–8 days. CJC-1295 "without DAC" — commonly called Modified GRF 1-29 (mod GRF 1-29) — retains the four stabilizing amino acid substitutions that confer DPP-IV resistance but lacks the albumin-binding group, resulting in a half-life of approximately 30 minutes. These are pharmacokinetically distinct compounds. Research findings from one should not be applied to the other without explicit acknowledgment of the difference.
Does CJC-1295 preserve pulsatile growth hormone secretion?
Based on published human data, yes — at the doses studied. Ionescu and Frohman (2006) found that pulse frequency and magnitude were unaltered one week after a single CJC-1295 injection in healthy men, despite a 7.5-fold increase in trough GH levels and a 45% rise in IGF-1. Preserved pulsatility is considered relevant because many physiological effects of GH are associated with its pulsatile rather than continuous secretion pattern.
Is CJC-1295 FDA approved or permitted in competitive sport?
No to both. CJC-1295 is not FDA approved for any therapeutic use in humans. The World Anti-Doping Agency prohibits it under Section S2 of the WADA Prohibited List, covering peptide hormones, growth factors, and related mimetics. Validated detection methods for CJC-1295 in plasma have been published in peer-reviewed journals. Athletes subject to WADA rules are prohibited from using it in any context, in-competition or out-of-competition.
Go deeper: This compound is one of 48 documented in the Legendary Labz Peptide Research Guide — a 224-page, evidence-tiered reference with primary citations throughout. Read a free compound profile.
Research use only. Not intended for human use. Not FDA approved. This article documents published scientific literature for educational and reference purposes and is not medical advice; nothing here is intended to diagnose, treat, cure, or prevent any disease, or to recommend human use of any compound. All citations link to primary sources — read them in full. Must be 18+.