CJC-1295: the long-acting GHRH analog with two very different forms

CJC-1295 is a synthetic analog of human growth hormone releasing hormone built on the shortest fully bioactive GHRH fragment, GHRH(1-29). it was developed by ConjuChem Biotechnologies in the early 2000s using a maleimide linker chemistry called DAC, designed to covalently tether the peptide to circulating albumin and extend its half-life from minutes to days.

what is CJC-1295?

CJC-1295 is two distinct molecules sold under one name. the long-acting DAC variant has a maleimide linker that binds plasma albumin and an effective half-life of roughly a week. the no-DAC variant has the same stabilizing substitutions but no linker, with a half-life of about 30 minutes. they require dose ranges that differ by roughly an order of magnitude.

both variants share four substitutions on the GHRH(1-29) backbone: a D-Ala at position 2 that blocks the enzyme DPP-IV from cleaving the N-terminus, a Gln at position 8 that prevents in-vial deamidation, an Ala at position 15 that increases GHRH receptor binding affinity, and a Leu at position 27 that prevents oxidation of the original methionine residue [1]. on top of that stabilized backbone, the DAC variant carries a maleimidopropionic-acid linker on the C-terminal lysine. that linker is a Michael acceptor: it reacts selectively with free thiols, and the only abundant free thiol in plasma is Cys34 on albumin. once the peptide finds an albumin molecule, the bond is essentially irreversible, and the whole conjugate inherits albumin's roughly 19-day circulating half-life [2].

the result is a pharmacologic split that runs through everything else on this page. the DAC variant produces continuous GHRH receptor occupancy and is dosed weekly. the no-DAC variant (often labeled modified GRF(1-29) or mod GRF 1-29) produces short receptor-engagement bursts and is typically dosed one to three times daily. confusingly, both are sold as "CJC-1295" in the research peptide market, and the dose ranges differ by about 10x. that mislabeling problem is one of the unique safety considerations for this peptide family.

how does it work?

both variants bind the GHRH receptor on pituitary somatotropes and switch on the same cAMP-PKA-CREB cascade that drives GH synthesis and release. downstream, GH binds hepatic GH receptors and stimulates IGF-1. the difference between the two variants is not what receptor they hit but how long they sit on it.

the GHRH receptor is a class B G-protein-coupled receptor on the anterior pituitary, first cloned in 1992 by the Mayo and Thorner labs [3]. when CJC-1295 docks into it, the receptor activates Gas, which raises intracellular cAMP, activates protein kinase A, phosphorylates the transcription factor CREB, and drives expression of Pit-1 and the GH gene. the somatotrope synthesizes new GH and releases stored GH from dense-core granules. circulating GH then binds GH receptors on hepatocytes, which produce IGF-1, the molecule that mediates most of the downstream anabolic and metabolic effects classically attributed to GH.

the most interesting pharmacology question for the DAC variant is whether continuous GHRH receptor stimulation flattens out the natural pulse pattern of GH release. counterintuitively, Ionescu and Frohman showed that pulsatility is largely preserved on DAC because the somatostatin oscillator in the hypothalamus is still active and still gates GH release on top of the elevated GHRH tone [4]. a useful conceptual frame: the no-DAC variant amplifies the body's natural rhythm in short bursts, while the DAC variant raises the baseline the rhythm sits on top of.

what does the evidence show?

the published human evidence is essentially one Phase 1 program and one halted Phase 2. Teichman and colleagues in 2006 showed that a single subcutaneous dose of CJC-1295 DAC produced two- to ten-fold elevations in mean GH and 1.5- to 3-fold elevations in IGF-1 lasting 6 to 11 days. a Phase 2 in HIV-associated lipodystrophy started enrollment but was halted in 2006 after a cardiovascular death, and no sponsor has restarted development since.

the Phase 1 single-ascending-dose study in healthy adults remains the foundational CJC-1295 dataset [1]. the most common adverse events were injection-site reactions and headache, with one transient flushing event reported. Ionescu and Frohman's multiple-dose study followed soon after and confirmed that pulsatility was preserved through repeat dosing [4]. the Phase 2 in HIV-lipodystrophy (ClinicalTrials.gov NCT00267527) enrolled 192 participants on weekly dose-escalation to 240 micrograms per kilogram. it was halted in July 2006 after a cardiovascular death in an Argentina-site participant. the attending physician attributed the death to pre-existing coronary disease rather than the study drug, but ConjuChem discontinued the program and never restarted it [5]. a once-daily mouse rescue study in GHRH-knockout animals supported the mechanism by showing that CJC-1295 normalized growth in animals that could not produce their own GHRH [6].

the broader evidence base for the drug class comes from related GHRH analogs. tesamorelin, a different modified full-length GHRH that completed a Phase 3 program in HIV-associated lipodystrophy, reduced visceral fat by roughly 15 percent in the Falutz trial and serves as the cleanest example of where the GHRH-analog drug class can succeed [7]. what is missing for CJC-1295 specifically is any modern controlled trial in healthy adults targeting body composition, any controlled CJC plus ipamorelin combination trial, any chronic-safety database beyond the halted Phase 2 window, and any independent verification of community-market product identity at scale.

regulatory status

CJC-1295 has no FDA-approved indication. it was nominated to the FDA's 503A bulk drug substances list in 2023 and placed in Category 2, which signals significant safety concerns. the nomination was withdrawn in September 2024, removing CJC-1295 from Category 2 on procedural grounds rather than as a positive safety determination. the World Anti-Doping Agency lists CJC-1295 explicitly on the prohibited list at all times.

the FDA Category 2 listing in September 2023 reflected both the limited human safety database and the unique DAC chemistry. removal from Category 2 in 2024 was procedural: the nominator withdrew the nomination, so the substance fell off the list, but it was not moved to Category 1 (the "may be compounded" set). CJC-1295 is therefore not in the permitted-for-503A-compounding pool as of writing. the WADA prohibited list places CJC-1295 under category S2.2 (growth hormone, its fragments, and releasing factors), naming it explicitly. any athlete in a WADA-tested sport should be aware that use is banned in and out of competition.

safety profile and side effects

the Phase 1 program reported injection-site reactions and headache as the most common adverse events. mechanistically expected GH-axis side effects include fluid retention, paresthesias, and mild glucose dysregulation. the halted Phase 2 cardiovascular death is the largest negative-signal datapoint in the published record, with contested causality. chronic-use safety beyond a year is essentially uncharacterized.

injection-site reactions including redness and itching were the most frequent adverse events across the Phase 1 dose-escalation program [1]. fluid retention and paresthesias are mechanistically expected for any GH-axis stimulator: GH drives sodium retention and the resulting volume expansion can produce mild peripheral edema and transient nerve compression symptoms. glucose handling is the side effect most worth highlighting on the safety side. GH is counter-regulatory to insulin: it antagonizes insulin action, promotes lipolysis, and tends to raise fasting glucose and HbA1c modestly. chronic IGF-1 elevation does not fully offset that effect [8].

the unique safety consideration for CJC-1295 DAC is the continuous GHRH receptor occupancy and the resulting risk of chronic supraphysiologic IGF-1 elevation over years. chronic high IGF-1 is the biological backbone of the acromegaly-shaped phenotype and is associated in population studies with increased risk of certain cancers, although no cancer signal emerged in the short Phase 2 window. the second unique consideration is the variant-mislabeling problem. a user who believes they are dosing no-DAC at typical community ranges (around 100-200 micrograms) but receives DAC variant could be exposed to roughly 10x the intended weekly burden. vendor LC-MS verification is the practical mitigation but is rarely available to end users.

where it fits in peptide science

CJC-1295 sits in a small family of GHRH-axis tools. its closest relatives are tesamorelin, sermorelin, and the ghrelin-receptor agonist ipamorelin. it shares the GHRH(1-29) backbone with sermorelin and the no-DAC version is essentially a stabilized sermorelin. the DAC version is a worked example of a generalizable medicinal-chemistry strategy called albumin tethering.

the natural comparison is tesamorelin, the only GHRH analog with FDA approval and a complete Phase 3 program. tesamorelin uses a different stabilization strategy (an N-terminal trans-3-hexenoyl modification that blocks DPP-IV) and has a half-life of about 30 minutes, similar to the no-DAC CJC-1295 variant. its approved use in HIV-associated lipodystrophy is the cleanest clinical proof-of-concept for the GHRH-analog drug class.

a related but mechanistically distinct option is ipamorelin, a pentapeptide that acts at the ghrelin receptor (GHSR-1a) rather than the GHRH receptor. ghrelin-receptor agonists and GHRH analogs target different cells on the somatotrope and combine synergistically, which is the basis of the popular CJC plus ipamorelin community stack. no controlled trial of that specific stack has been published. for broader context on how the GH axis interacts with the GLP-1 family that includes semaglutide and tirzepatide, see our free peptides and your body module.