CJC-1295 FAQ: 28 Questions from the Research Literature
Frequently Asked Questions: CJC-1295
CJC-1295 is a 29-amino-acid synthetic analog of growth hormone-releasing hormone (GHRH), first synthesized by ConjuChem Biotechnologies. It was investigated in Phase I/II human trials for adult GH deficiency and body composition endpoints. Four amino acid substitutions confer resistance to DPP-IV degradation; the DAC form adds albumin-binding for an extended half-life of 5.8–8.1 days [1][4]. CJC-1295 is not FDA-approved for any indication.
CJC-1295 binds GHRH receptors in the anterior pituitary, stimulating pulsatile release of endogenous growth hormone via the Gs-cAMP-PKA-calcium signaling cascade. Downstream, GH drives hepatic IGF-1 synthesis. In the Teichman 2006 Phase II trial, single doses elevated mean plasma GH 2- to 10-fold for 6+ days and IGF-1 by 1.5- to 3-fold for 9–11 days [1].
The DAC (Drug Affinity Complex) modification adds a lysine-reactive maleimide group that covalently binds albumin, extending plasma half-life from approximately 30 minutes (no-DAC) to 5.8–8.1 days (DAC) in published human pharmacokinetic studies [1]. No-DAC (Modified GRF 1-29) retains DPP-IV resistance from the four amino acid substitutions but clears from circulation far faster than the albumin-conjugated form.
Adverse events documented in published studies include injection-site reactions, transient flushing and vasodilation (at 90–125 mcg/kg in the Teichman 2006 trial [1]), headache, water retention, and elevated appetite. The FDA raised immunogenicity concerns for compounded injectable CJC-1295 in 2024. A Phase II trial was halted in 2006 following a participant death [18].
No direct testosterone-raising mechanism has been identified. CJC-1295 targets the GH/IGF-1 axis exclusively; no direct testosterone elevation has been demonstrated in peer-reviewed studies. Some animal research notes indirect anabolic signaling through IGF-1 that may interact with androgen receptor pathways, but no testosterone elevation has been measured in CJC-1295 trials.
CJC-1295 mimics the N-terminal active fragment of native GHRH(1-29), binding GHRH-R on somatotroph cells and triggering calcium-mediated GH exocytosis. Four substitution mutations (Ala2, Gln8, Ala15, Leu27) confer protease resistance absent in the native peptide [11]. The Ala2 substitution specifically blocks DPP-IV cleavage. The DAC modification then adds covalent albumin binding for extended half-life.
In preclinical and early clinical research, the CJC-1295 plus ipamorelin combination is studied for synergistic amplification of GH pulse amplitude. CJC-1295 increases baseline GH secretion via GHRH-R; ipamorelin (a GHSR agonist) triggers an acute GH pulse via a distinct receptor. Co-activation of both receptors doubled cAMP response vs. GHRH-R alone in vitro [8]. Body composition and fat metabolism outcomes are studied in preclinical models [9][10].
Combined use adverse events reported in clinical and observational data include injection-site erythema, flushing, transient headache, increased hunger, joint discomfort, and water retention. Ipamorelin monotherapy produced no significant ACTH or cortisol release in swine at doses more than 200-fold above the GH-effective dose [7]. CJC-1295 was well tolerated at 30–60 mcg/kg in the Teichman 2006 trial [1].
Pharmacokinetic studies in humans showed peak plasma GH elevation within 2–6 hours of a single subcutaneous injection. Mean plasma GH levels remained elevated for 6 days post-injection in the CJC-1295 DAC arm of the Teichman et al. 2006 Phase II trial [1]. IGF-1 elevation was sustained for 9–11 days post-injection.
The Teichman 2006 Phase II trial reported CJC-1295 well tolerated at 30–60 mcg/kg with no serious adverse reactions [1]. A Phase II trial in HIV patients with visceral obesity was halted in 2006 following a participant death [18]. The FDA placed CJC-1295 on the 503A compounding no-go list in 2024 citing immunogenicity concerns. This site documents the research literature only.
Published dosing protocols in human trials used subcutaneous administration; preclinical rodent studies used intraperitoneal injection at 30–500 mcg/kg [1][9]. This site summarizes published literature only. CJC-1295 is not FDA-approved and no validated human therapeutic protocol exists. The CJC-1295 dosage in published trials page covers what the studies actually administered.
The two variants serve different research models: DAC (long-acting, weekly dosing in studies) and no-DAC (also called Modified GRF 1-29, short-acting, pulsatile-dosing models). The Teichman 2006 study used the DAC form in humans [1]; no direct head-to-head efficacy trial has been published. No superiority conclusion is supported by the available evidence.
Research on muscle-building peptides documents acromegaly-like risks with supraphysiological GH elevation (soft tissue overgrowth, insulin resistance), injection-site complications, and glucose metabolism disruption. CJC-1295 studies in rodents observed dose-dependent IGF-1 elevation without overt organ toxicity at standard research doses [5], but the acromegaly literature establishes physiological risks of sustained GH excess.
No direct testosterone-raising mechanism has been identified in published studies. CJC-1295 targets the GH/IGF-1 axis exclusively. Some animal research has noted indirect anabolic signaling through IGF-1 that may interact with androgen receptor pathways, but no testosterone elevation has been measured in CJC-1295 trials. The HPG axis (which governs testosterone) is not a primary target of CJC-1295.
CJC-1295 is not FDA-approved for any indication. It was listed by the FDA in 2024 on the bulk drug substance no-go list for Section 503A compounding pharmacies, citing no clinical necessity demonstrating advantage over approved alternatives and immunogenicity concerns for injectable formulations from potential peptide aggregation.
Published pharmacokinetic data: CJC-1295 without DAC has a plasma half-life of approximately 30 minutes in rodent models; CJC-1295 with DAC demonstrated a mean half-life of 5.8–8.1 days in the Teichman et al. Phase II human trial (2006, JCEM) [1]. Native GHRH(1-29) (sermorelin) has a half-life of approximately 10–20 minutes in humans [13].
Rodent studies with GHRH analogs and GHSR agonists separately report reductions in adipose tissue and preservation of lean body mass. Ipamorelin produced dose-dependent bone growth and body weight gain in rats [9][10]; CJC-1295 restored normal body composition in GH-deficient mice [5]. No randomized controlled trial in humans has examined the CJC-1295/ipamorelin combination specifically for weight loss or muscle building as primary endpoints.
CJC-1295 binds GHRH-R on anterior pituitary somatotrophs, activating adenylate cyclase via Gs-coupling, elevating intracellular cAMP, and triggering calcium-dependent GH secretory granule exocytosis [15]. Four substitution mutations (Ala2, Gln8, Ala15, Leu27) confer in vivo stability by resisting DPP-IV and endopeptidase cleavage [11]. The cryo-EM structure of the GHRH-GHRH-R-Gs complex was resolved at 2.6 Angstrom in 2020 [12].
CJC-1295 is a peptide, not a steroid. It is a 29-amino-acid polypeptide with no steroidal ring structure. Its mechanism — GHRH receptor agonism triggering the Gs-cAMP-PKA-calcium cascade — is entirely distinct from androgenic/anabolic steroids, which act on nuclear androgen receptors. The two compound classes differ in structure, target receptor, and mechanism.
No published study has identified hair loss as a direct adverse event of CJC-1295. Elevated IGF-1 has theoretical associations with androgenic pathways in some models, but no clinical or preclinical data specifically links CJC-1295 to alopecia. Hair loss does not appear in the adverse event records of the published human trials [1][3].
Sermorelin is the first 29 amino acids of native GHRH with no protective substitutions, yielding a plasma half-life of 10–20 minutes [13]. CJC-1295 carries four mutations and the optional DAC modification, extending half-life from approximately 30 minutes (no-DAC) to 5.8–8.1 days (DAC). No direct head-to-head clinical trial has been published. The sermorelin vs CJC-1295 distinction is structural and pharmacokinetic, not based on comparative efficacy data.
CJC-1295 without DAC is largely cleared within 4–6 hours in rodent models. The DAC form demonstrated sustained elevation of mean plasma GH and IGF-1 concentrations for up to 14 days post-injection in the 2006 human Phase II study [1]. Detection studies confirm CJC-1295 measurable in human plasma at below 50 pg/mL using immunoaffinity-assisted LC-HRMS [20] and in equine plasma at 180 pg/mL [19].
MK-677 (ibutamoren) is an oral GHSR agonist with a half-life of approximately 4.7 hours; CJC-1295/ipamorelin is an injectable GHRH/GHSR dual combination. The two approaches differ in route, half-life, regulatory status, and available clinical evidence [16]. No direct comparative trial has been published. MK-677 Phase I/II human data are available; CJC-1295/ipamorelin combination data are primarily preclinical and mechanistic.
The Teichman et al. 2006 JCEM Phase II trial used single-dose CJC-1295 DAC at 30, 60, 90, or 125 mcg/kg subcutaneously in healthy adults [1]. Preclinical rodent studies have used 100–500 mcg/kg across multiple routes. No validated human therapeutic dose exists, as CJC-1295 is not FDA-approved. See CJC-1295 DAC vs no DAC for the pharmacokinetic context.
No studies have examined CJC-1295 in adolescent populations. Growth plate closure timing is governed by estrogen and androgen signaling, not solely GH levels. Extrapolating adult GH-axis research to adolescent height is not supported by the published literature. No clinical basis exists for this application in the CJC-1295 research record.
No published clinical study has specifically examined GH axis rebound or suppression following CJC-1295 discontinuation. The compound stimulates pituitary GH release rather than replacing it, which suggests endogenous axis preservation in principle, but long-term follow-up data examining post-discontinuation GH dynamics are absent from the literature.
Flushing is attributed to the vasodilatory effects of elevated GH and potentially to direct peptide-induced nitric oxide signaling. The Teichman 2006 trial noted transient vasodilatory reactions in human subjects at 90–125 mcg/kg [1]. The mechanism is believed analogous to niacin-flush pathways in peripheral vasculature — peripheral vasodilation causing skin redness and warmth.
CJC-1295 is fully synthetic. It was designed and synthesized by ConjuChem Biotechnologies and does not occur in nature [4]. It is an analog of the endogenous peptide GHRH, modified at four positions for protease resistance and, in the DAC form, with an additional maleimide-lysine group for albumin binding. The natural ligand GHRH exists endogenously; CJC-1295 does not.