# CJC-1295 Medicinal — A scholarly catalog of the long-acting GHRH analog evidence base > Peer-reviewed summaries of CJC-1295 pharmacology: the Drug Affinity Complex mechanism, sustained GH and IGF-1 elevation in human Phase 1 trials, pulsatility preservation, and anti-doping status. A scholarly examination of the pharmacology, human pharmacokinetic data, and regulatory history of CJC-1295 — a 30-amino-acid synthetic analog of growth hormone-releasing hormone whose covalent albumin-binding modification extends plasma persistence from minutes to days. ## The short version CJC-1295 is a synthetic peptide analog of the growth-hormone-releasing hormone (GHRH) that the hypothalamus normally makes. Its distinctive feature is a molecular modification — called the Drug Affinity Complex, or DAC — that causes it to latch onto a common blood protein (albumin) after injection, keeping it active for roughly six to eight days rather than the ten to thirteen minutes native GHRH lasts. That long duration has made it a focus of early human pharmacology research: two published trials in healthy adults found that a single dose could raise growth hormone concentrations two to tenfold for nearly a week and keep IGF-1 (the liver's downstream messenger) elevated for nine to eleven days. Phase 2 clinical development was discontinued before any efficacy studies were completed, and the compound has never been approved for human use by any regulatory agency. It is prohibited in sport by the World Anti-Doping Agency. For a plain-English account of what research-use communities report about effects and cautions, see [the effects page](/effects). ## What Is CJC-1295? CJC-1295 is a 30-amino-acid synthetic peptide analog of the 1–29 active fragment of human growth hormone-releasing hormone (GHRH). The native molecule — a 44-residue neuropeptide synthesized in the arcuate nucleus of the hypothalamus — is responsible for driving pulsatile growth hormone secretion from anterior pituitary somatotroph cells. Its 1–29 fragment retains full receptor-binding activity but is susceptible to rapid proteolytic clearance by dipeptidyl peptidase IV (DPP-IV), yielding a plasma half-life of approximately 10 to 13 minutes under physiological conditions [6]. The structural design of CJC-1295 addresses this vulnerability through two modifications applied in tandem. First, four amino acid substitutions — Ala2→D-Ala, Gln8→Ala, Ala15→Gly, Leu27→Met — confer resistance to DPP-IV proteolysis and alter receptor affinity in ways that preserve agonist activity [1]. Second, and more consequentially, a C-terminal maleimidopropionic acid moiety constitutes the Drug Affinity Complex (DAC): following subcutaneous injection, the maleimide group undergoes covalent conjugation to free thiol groups on circulating plasma albumin — predominantly Cys-34 — creating a long-lived peptide-albumin depot from which active peptide is slowly released over the ensuing 6 to 8 days [6]. The compound was identified and formally characterized in a 2005 study by Jette et al., which demonstrated a 4-fold increase in growth hormone area under the curve over a two-hour window in Sprague-Dawley rats, with plasma bioactivity detectable by Western blot beyond 72 hours post-injection [1]. This pharmacokinetic distinction — a half-life measured not in minutes but in days — is the central pharmacological fact about CJC-1295 and the premise of its research program. The molecular weight of the fully modified peptide is 3,647.3 Da (CAS 863288-34-0). The compound does not have an approved therapeutic indication in any jurisdiction. Phase 2 clinical development was discontinued before efficacy studies in growth hormone-deficient populations could be completed. CJC-1295 is listed under Section S2 of the World Anti-Doping Agency (WADA) Prohibited List as a peptide hormone, growth factor, and related substance — prohibited at all times, in-competition and out-of-competition, for athletes subject to anti-doping rules [7]. ## Pharmacokinetic Profile: The DAC Mechanism The transformation of a peptide with a 10-to-13-minute plasma half-life into one with a half-life of 5.8 to 8.1 days [2] is produced by the covalent bond between the maleimidopropionic acid group and plasma albumin thiols. Albumin, the most abundant plasma protein at approximately 40 g/L with a half-life of roughly 19 days, functions as a circulating pharmacokinetic depot. The resulting CJC-1295-albumin conjugate is released slowly into circulation, extending the compound's period of biological activity by several orders of magnitude relative to unmodified GHRH fragments [6]. This extended half-life has two practical consequences for research contexts. First, dosing intervals in animal models have been explored at once-daily, every-48-hour, and every-72-hour frequencies, with once-daily administration demonstrating superior normalization outcomes in GHRH-knockout mice [4]. Second, in human pharmacodynamic studies, single subcutaneous injections produced mean plasma GH concentrations elevated 2- to 10-fold for 6 or more days post-dose, and IGF-1 remained 1.5- to 3-fold above baseline for 9 to 11 days [2]. Multiple-dose regimens sustained IGF-1 above baseline for up to 28 days [2] — a cumulative GH/IGF-1 axis activation profile qualitatively unlike anything achievable with native GHRH or its shorter-lived analogs. The DAC modification also confers stability against DPP-IV proteolysis, the primary mechanism of rapid native-GHRH degradation. The D-Ala substitution at position 2 eliminates the canonical DPP-IV cleavage site, while the albumin conjugation creates steric barriers to enzymatic access [1][6]. Urinary metabolites of CJC-1295, when studied in analytical research settings, show rapid degradation at temperatures above 4°C and at pH below 7 [11] — findings that inform anti-doping sample handling protocols rather than clinical practice, given the compound's unapproved status. The albumin-bound form of CJC-1295 presents a distinctive complication for anti-doping detection: traditional mass spectrometry methods that excel at detecting free peptides are inadequate for the protein-conjugated form, which requires immunological detection approaches or specialized immunoaffinity enrichment steps prior to LC-HRMS/MS analysis [8][9][10]. ## Human Pharmacodynamic Data: What the Phase 1 Trials Found Two randomized, placebo-controlled, double-blind ascending-dose studies in healthy adult humans constitute the totality of prospective controlled human pharmacodynamic data for CJC-1295. Teichman et al. (2006) enrolled healthy adults across dose cohorts of 30, 60, 120, and 180 mcg/kg subcutaneous and reported that doses of 30 and 60 mcg/kg produced the most favorable pharmacodynamic profiles: mean plasma GH concentrations increased 2- to 10-fold and remained elevated for 6 or more days; IGF-1 rose 1.5- to 3-fold for 9 to 11 days; and no serious adverse reactions were observed across these dose levels [2]. The estimated plasma half-life, derived from pharmacokinetic modeling in the same study, was 5.8 to 8.1 days. Ionescu and Frohman (2006) examined the specific question of pulsatile GH secretion architecture under CJC-1295 stimulation, enrolling healthy men aged 20 to 40. Single subcutaneous doses of 60 or 90 mcg/kg produced a 7.5-fold increase in basal GH levels, a 46% increase in mean GH concentration, and a 45% increase in IGF-1 — while GH pulse frequency and magnitude remained statistically indistinguishable from pre-treatment patterns [3]. This preservation of pulsatile GH secretory architecture under sustained hormonal stimulation is pharmacologically notable: exogenous growth hormone administration abolishes pulsatility by saturating feedback mechanisms, whereas a GHRH analog acts upstream, amplifying the endogenous pulse generator's output without replacing it. Proteomic analysis of the same CJC-1295 perturbation was carried out by Sackmann-Sala et al. (2009), who administered 60 to 90 mcg/kg to 11 healthy adult males and characterized serum protein profile changes via two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry. Five serum protein spots showed statistically significant intensity changes: decreases in apolipoprotein A1 and transthyretin isoforms, and increases in beta-hemoglobin, a C-terminal albumin fragment, and an immunoglobulin fragment. IGF-1 elevation correlated significantly with the immunoglobulin/albumin fragment spot (Pearson r2 = 0.668, P = 0.002) [5]. These proteomic shifts represent the first systematic characterization of downstream molecular consequences beyond the GH/IGF-1 axis itself, though their clinical significance remains unstudied. Phase 2 clinical development was discontinued following an unrelated adverse event in a trial participant. No human efficacy studies in growth hormone-deficient populations were completed, and no therapeutic indication was filed or approved in any jurisdiction. ## Research Context: The GH Axis, Somatopause, and Related Analogs The endocrine rationale for interest in long-acting GHRH analogs derives from the physiology of the GH/IGF-1 axis across the human lifespan. Growth hormone secretion peaks in adolescence and declines progressively — a phenomenon termed somatopause — beginning as early as the third decade of life. The clinical manifestations of age-related GH axis decline include increased visceral adiposity, reduced lean body mass, decreased bone mineral density, and impaired quality of life, a constellation that overlaps substantially with recognized adult growth hormone deficiency syndrome [16]. A 2024 clinical review of adult GHD by Aversa et al. documented that, on average, 6 months of GH replacement therapy increases lean body mass by approximately 4.3% and decreases fat mass by approximately 13.1%, though adverse effects including fluid retention (11–100% prevalence depending on study population), carpal tunnel syndrome (7–50%), and arthralgias (14–77%) are common — and approximately 3% of treated patients develop type 2 diabetes [16]. The stimulation testing required to diagnose adult GHD remains technically demanding, costly, and carries its own adverse effect risk [16]. A 2024 study in elderly hospitalized patients (mean age 82) with low IGF-1 found that GHRH/arginine stimulation produced a peak GH response of 14.8 mcg/L (range 2.76–47.4 mcg/L) in 16 of 17 subjects — demonstrating that pituitary somatotroph secretory capacity is largely preserved in advanced age [18]. The predominant driver of somatopause appears to be reduced hypothalamic GHRH output rather than intrinsic pituitary failure, a finding that provides mechanistic support for the pharmacological strategy of GHRH analog stimulation as a research intervention. CJC-1295 occupies a specific niche within the GHRH analog class: it is structurally distinct from sermorelin (GHRH 1–29 without DAC modification, substantially shorter-acting) and from tesamorelin (GHRH 1–44 with a trans-3-hexenoic acid modification, FDA-approved for HIV-associated lipodystrophy). These structural analogs appear as reference compounds in anti-doping detection studies alongside CJC-1295 [9][10][11] but differ in pharmacokinetic profiles and regulatory status. Research combining CJC-1295 with ipamorelin — a GH secretagogue acting via the ghrelin receptor, a complementary upstream pathway — showed improved maximum tetanic tension in murine glucocorticoid-induced muscle atrophy models compared to either compound alone [15]. ## Editorial Approach of This Site CJC-1295 Medicinal is an independent scholarly publisher presenting summaries of the peer-reviewed research literature on CJC-1295. The evidence base for this compound is narrow by the standards of approved pharmacological agents: three Phase 1 pharmacodynamic publications in healthy adults, one animal model study in GHRH-knockout mice, one proteomic study, a collection of anti-doping analytical method papers, and a small netnographic observation of self-reported use. That narrowness is rendered here with appropriate epistemic weight — claims are attributed to specific studies, dose values are tied to specific trial arms and species, and regulatory and safety uncertainties are presented without minimization. All dosing information on this site describes research-context administration protocols as documented in the cited primary literature. Nothing on this site constitutes medical advice, and the compound is not approved for human therapeutic use by any regulatory agency. The compound's research-chemical status and WADA prohibition are noted throughout as material facts about its regulatory classification. --- An independent scholarly digest of the peer-reviewed CJC-1295 literature — not a clinic, not a vendor, not medical advice.