# CJC-1295 Research: Human PK, Detection, and the GHRH-Analog Record > CJC-1295 research reviewed in sequence: the 5.8-8.1 day half-life, basal GH +7.5-fold, IGF-1 +45% at one week, the ipamorelin rationale, and the anti-doping detection assays. Every figure cited. From the 2005 rat albumin-bioconjugate proof to the 2025 detection methods — the human pharmacokinetics, the two-receptor ipamorelin rationale, and the analytical arms race. ## CJC-1295 as a Long-Acting GHRH Analog CJC-1295 is a long-acting GHRH analog: it activates the same pituitary receptor as the body's own growth-hormone-releasing hormone, but it survives in circulation for days rather than minutes. Native GHRH(1-29) is cleaved almost immediately by dipeptidylpeptidase-IV. CJC-1295 carries four substitutions — D-Ala2, Gln8, Ala15, Leu27 — that stabilize the helix and block that cleavage, and in vitro the modified peptide is demonstrably DPP-IV-resistant [2]. The receptor it targets, GHRHR, is a class B G-protein-coupled receptor on pituitary somatotrophs. Binding activates Gs, adenylate cyclase, cAMP and PKA, driving GH gene transcription and pulsatile GH release; the released GH then acts on the liver through JAK2/STAT5 to raise IGF-1 [2]. As a class, GHRH and its synthetic analogues — the family that also contains sermorelin and tesamorelin — were synthesized in 2025 by a Nature Reviews Endocrinology review describing receptor signaling and the rationale for long-acting analog design [11]. ## What the Human and Animal Studies Actually Report The CJC-1295 benefits described online reduce, in the peer-reviewed record, to a specific set of measured endocrine changes — elevated growth hormone and IGF-1, sustained over days. We report them as the studies reported them, not as outcomes a person should expect. In healthy adults, single subcutaneous doses of 30 or 60 ug/kg produced dose-dependent 2- to 10-fold increases in mean plasma GH lasting six days or more, and 1.5- to 3-fold increases in IGF-1 lasting nine to eleven days; after multiple doses IGF-1 stayed above baseline up to 28 days [1]. In healthy young men, a single 60 or 90 ug/kg dose raised basal GH about 7.5-fold and lifted mean GH roughly 46% and IGF-1 roughly 45% one week later [3]. The animal record anchors the same axis. In GHRH-knockout mice, 2 ug of CJC-1295 once every 24 hours fully normalized body weight and length and raised pituitary GH mRNA, while dosing every 48-72 hours was progressively less effective [4]. None of this establishes a benefit for healthy humans; it establishes that the compound does, reproducibly, what a GHRH analog is designed to do. ## Measured Outcomes in Controlled Studies The CJC-1295 results worth citing are the ones from controlled pharmacokinetic and pharmacodynamic studies. Four numbers carry most of the weight. First, half-life: an estimated 5.8 to 8.1 days for the DAC variant in healthy adults [1]. Second, IGF-1 duration: elevation persisting up to 28 days after multiple doses [1]. Third, basal GH: a roughly 7.5-fold rise after a single dose [3]. Fourth, the preclinical exposure gain: a four-fold increase in GH area-under-the-curve over the unconjugated peptide in rats, with the albumin conjugate still detectable in plasma beyond 72 hours [2]. A 2009 study added a different kind of result — a reproducible shift in the serum proteome (decreased apolipoprotein A1 and a transthyretin isoform; increased an albumin fragment and immunoglobulin species), with the immunoglobulin/albumin-fragment signal tracking IGF-1 linearly, identifying candidate biomarkers of GH/IGF-1 axis activation [5]. ## CJC-1295 and Ipamorelin: The Two-Receptor Rationale The CJC-1295 ipamorelin pairing is the most-discussed combination in this space, and its logic is mechanistic, not trial-proven. GHRH analogs and growth-hormone-releasing peptides act through two distinct receptors — the GHRH receptor and the ghrelin/GHS receptor — and when stimulated together they produce GH release greater than the sum of either alone [12]. Ipamorelin is a selective GH secretagogue that releases GH with minimal ACTH/cortisol or prolactin spillover, which is why it is the common research partner for a GHRH analog [12]. That is the entire rationale: two levers on one pump. What does not exist is a controlled human efficacy trial of the specific CJC-1295/ipamorelin combination in healthy adults [12]. The synergy is well-supported at the receptor level; the real-world combination outcomes people ask about have not been measured in a controlled setting. ## How CJC-1295 Sits Among GHRH Analogs (Sermorelin, Tesamorelin) The CJC-1295 vs sermorelin comparison is really a comparison of duration. Sermorelin is hGRF(1-29) itself — the active fragment, unmodified — and it is short-acting. Tesamorelin is a stabilized GHRH analog that reached FDA approval for HIV-associated lipodystrophy. CJC-1295 sits at the far end of the duration spectrum: the DAC variant's albumin conjugation gives it the multi-day half-life none of the others have [1][2]. The 2025 Nature Reviews Endocrinology review situates all three within one analog class and one receptor pharmacology [11]. The distinction that matters for CJC-1295 specifically is internal — DAC versus no-DAC — and it gets [its own page](/dac-vs-no-dac). ## How CJC-1295 Is Detected in Anti-Doping Testing Detection is the lens through which most of the recent CJC-1295 literature was written, because the compound is prohibited in sport and laboratories had to learn to find it. The foundational analytical event was the 2010 structural identification of CJC-1295 by high-resolution LC-MS/MS as the active ingredient in a seized 'GHRH' preparation of unknown composition [6]. Confirmatory approaches followed: qualitative identification of GHRH analogs in human plasma by immunoaffinity purification and LC-MS [9], an antibody-free ultrafiltration-based assay for GHRH analogs [7], and reviews documenting the broader analytical advances against synthetic GHRH analogs in sport [8]. Recent methods extend coverage — a 2024 approach for 2-10 kDa peptidic analytes (the size class containing CJC-1295) [13] and a 2025 nano-LC-MS method for GHRH and its analogs in urine [14]. The [anti-doping detection](/research) record is, in short, mature and still advancing. --- A scroll-told review of the CJC-1295 literature, read top to bottom in the order the evidence accrued — the DAC and no-DAC tracks kept apart, every figure logged to its study and the human gaps left visibly open; no clinic behind the rail and nothing here dispensed or for sale.