CJC-1295 with DAC — Molecular Weight, Sequence & Half-Life Reference

01What is CJC-1295 (with DAC)?

CJC-1295 with DAC is a 30-residue analog of growth hormone-releasing hormone. Its first 29 residues are tetrasubstituted GRF(1-29) — D-Ala at position 2, Gln at 8, Ala at 15 and Leu at 27, each substitution chosen to resist enzymatic degradation. The thirtieth position carries a lysine bearing a maleimidopropionyl group: the Drug Affinity Complex, or DAC, which forms a covalent bond with cysteine-34 of circulating serum albumin after administration.

That single addition is responsible for a half-life of 5.8 to 8.1 days in healthy adults. CJC-1295 without DAC — sold as Mod GRF 1-29 or tetrasubstituted GRF(1-29) — has the same 29-residue core and a reported half-life around thirty minutes. Same peptide backbone, roughly a 280 Da difference in mass, and roughly a three-hundred-fold difference in duration. Any source that quotes one half-life for "CJC-1295" without specifying the form is describing two different molecules at once.

Clinical development was discontinued. The compound is referenced here for its pharmacology and its chemistry; there is no approved product and no current registered clinical programme.

02Molecular information

03Amino acid sequence

Structural modifications

Built on human GHRH(1-29), i.e. sermorelin, with four substitutions plus a C-terminal extension. The four substitutions are D-Ala at position 2 (replacing L-Ala, blocking DPP-4 cleavage at the N-terminus), Gln at position 8 (replacing Asn, removing an asparagine deamidation site), Ala at position 15 (replacing Gly), and Leu at position 27 (replacing Met, removing a methionine oxidation site). These four together define the 'tetrasubstituted GRF(1-29)' core that is shared identically with CJC-1295 without DAC. The DAC element is the additional thirtieth residue: a lysine whose epsilon-amino group is acylated with 3-maleimidopropionic acid, giving N-epsilon-(3-maleimidopropionyl)-lysine. The maleimide is a thiol-reactive Michael acceptor that, after injection, forms a covalent thioether bond in vivo with the free cysteine-34 thiol of circulating serum albumin. The C-terminus is a primary amide. There are no disulfide bonds and no cyclisation within the peptide itself.

04Pharmacokinetic information

Half-life context

The primary human value is from Teichman et al., Journal of Clinical Endocrinology and Metabolism 2006, two randomised, placebo-controlled, double-blind ascending-dose trials of 28 and 49 days in healthy adults aged 21 to 61 receiving subcutaneous CJC-1295: the estimated half-life was 5.8 to 8.1 days. Ionescu and Frohman, in the same journal and year, describe the analogue as having an extended half-life of approximately 8 days, consistent with that range. This is a plasma half-life of the albumin-bound conjugate and is long precisely because covalent attachment to serum albumin makes the peptide's disposition track albumin turnover rather than free-peptide proteolysis. Effect duration is longer still and must be distinguished from the half-life: after a single injection, plasma growth hormone rose 2- to 10-fold for 6 days or more and IGF-I rose 1.5- to 3-fold for 9 to 11 days, while after multiple doses mean IGF-I remained above baseline for up to 28 days. The contrast with the DAC-free compound is the single most important number here and it differs by roughly two to three orders of magnitude: the FDA compounding docket submission gives approximately 30 minutes for CJC-1295 without DAC (Modified GRF 1-29), against 6 days with DAC. Any half-life figure quoted for 'CJC-1295' without specifying DAC status is therefore uninterpretable. No authoritative animal pharmacokinetic values were retrieved, and no data exist for paediatric, renal-impaired or hepatic-impaired populations.

05Research focus

Primary research areas

• long-acting GHRH receptor agonism
• albumin conjugation via drug affinity complex chemistry
• sustained GH and IGF-I elevation
• preservation of pulsatile GH secretion
• phase 1 and 2 pharmacokinetics in healthy adults
• growth hormone deficiency and lipodystrophy (discontinued programmes)

Research context

CJC-1295 with DAC is a synthetic analogue of the first 29 residues of human growth hormone-releasing hormone, developed by ConjuChem Biotechnologies, that agonises the GHRH receptor to stimulate pituitary growth hormone secretion. Its core is tetrasubstituted GRF(1-29) - D-Ala2, Gln8, Ala15, Leu27 - modifications that block dipeptidyl peptidase-4 cleavage and remove deamidation and oxidation liabilities. What distinguishes the DAC form is a thirtieth residue, a lysine bearing an epsilon-amino 3-maleimidopropionyl group. This maleimide is a thiol-reactive Michael acceptor that forms a covalent thioether bond with cysteine-34 of circulating serum albumin after injection, so that the peptide's clearance follows albumin turnover instead of free-peptide proteolysis [4]. The pharmacological consequence is large. Teichman and colleagues conducted two randomised, double-blind, placebo-controlled ascending-dose trials of 28 and 49 days in healthy adults aged 21 to 61 and estimated a half-life of 5.8 to 8.1 days; a single subcutaneous injection raised plasma growth hormone 2- to 10-fold for six days or more and IGF-I 1.5- to 3-fold for 9 to 11 days, with mean IGF-I remaining above baseline for up to 28 days after repeated dosing, and no serious adverse reactions reported at 30 to 60 micrograms/kg [1]. Ionescu and Frohman addressed the physiologically important question of whether such continuous stimulation flattens the normal secretory rhythm. In healthy men aged 20 to 40 given single 60 or 90 microgram/kg doses, with 20-minute sampling over 12 overnight hours before and one week after injection, growth hormone pulse frequency and amplitude were unchanged; trough growth hormone rose 7.5-fold, mean growth hormone rose 46 percent and IGF-I rose 45 percent, and the IGF-I increase did not correlate with any parameter of pulsatile secretion, suggesting the basal elevation drove it [2]. Development reached phase 2 for lipodystrophy and growth hormone deficiency, and a phase 2 obesity trial (NCT00267527) is recorded as terminated [5]. The programme was halted following a participant death that the attending physician attributed to pre-existing coronary artery disease rather than treatment [4].

06Research evidence and limitations

Regulatory status

Investigational; never approved in any jurisdiction. Developed by ConjuChem Biotechnologies, it reached phase 2 for lipodystrophy and growth hormone deficiency, with a phase 2 obesity trial (NCT00267527) recorded as terminated; NCATS lists the substance's development status as failed. Development was halted after a participant death attributed by the attending physician to pre-existing coronary artery disease, with termination described as precautionary. In an FDA briefing document dated 4 December 2024, prepared for the Pharmacy Compounding Advisory Committee alongside evaluations of AOD-9604 and thymosin alpha-1, FDA proposed that no form of CJC-1295 be included on the 503A bulk drug substances list - explicitly naming CJC-1295 free base, CJC-1295 acetate, CJC-1295 DAC free base, CJC-1295 DAC acetate and CJC-1295 DAC trifluoroacetate - applying its four evaluation criteria of physicochemical characterisation, safety, evidence of effectiveness, and historical use in compounding [3]. CJC-1295 does not currently appear on FDA's Category 2 table; that page records it as previously nominated with the nomination withdrawn. CJC-1295 is named explicitly on the WADA Prohibited List under section S2 as a GHRH analogue, prohibited at all times, in and out of competition [6].

07Research material and sourcing notes

Reported research-use reconstitution information

Manufacturer technical documentation (ProSpec, CJC-1295 DAC, research reagent, purity greater than 97.0 percent by RP-HPLC, supplied as sterile-filtered white lyophilised powder, lyophilised with no additives): reconstitute in sterile 18 megaohm-cm water to a minimum concentration of 100 micrograms/mL, then dilute further into aqueous solutions as required. The same documentation recommends adding 0.1 percent HSA or BSA as a carrier protein for long-term storage and advises avoiding freeze-thaw cycles. No pH specification is given and no peer-reviewed solubility determination was retrieved. Note that the maleimide group is thiol-reactive and also hydrolyses over time in aqueous solution, so reducing agents and thiol-containing buffers should be avoided if the conjugation handle must remain intact. Laboratory handling information only; no dosing guidance is given or implied.

Reported storage and stability information

Manufacturer technical documentation (ProSpec): lyophilised powder should be kept desiccated below -18 C, and is stated to remain stable at room temperature for up to 3 weeks. Reconstituted material may be held at 4 C for 2 to 7 days; for longer periods store below -18 C, preferably with 0.1 percent HSA or BSA carrier protein added, and avoid repeated freeze-thaw cycles. No pharmacopoeial monograph or FDA-approved product specification exists for this substance, so there is no compendial storage standard. Source type: research-reagent manufacturer datasheet.

Identity and sourcing notes

The dominant identity problem in this compound is nomenclature, and it is severe enough to invalidate most label claims. 'CJC-1295' is used commercially for two chemically distinct peptides: the DAC form described here (30 residues, C165H269N47O46, 3647.2 Da, CAS 446262-90-4) and the DAC-free Modified GRF(1-29), also called tetrasubstituted GRF(1-29) or CJC-1295 no-DAC (29 residues, C152H252N44O42, 3367.9 Da, CAS 863288-34-0). They share an identical core sequence and differ only by Lys30 and its maleimidopropionyl group, but their half-lives differ by roughly two to three orders of magnitude. A supplier aggregator entry for CAS 863288-34-0 carries the contradictory synonyms 'CJC NO DAC' and 'CJC Dac' simultaneously. Verify DAC status by mass, not by product name: 3647 versus 3367 is unambiguous by high-resolution mass spectrometry. Beyond that, the salt form should be declared - FDA treats free base, acetate and trifluoroacetate as separate substances, acetate and TFA stoichiometry is variable and usually undeclared, and gross vial mass therefore overstates peptide content. The maleimide group hydrolyses over time in aqueous solution and reacts with any free thiol it encounters, so a COA ideally reports maleimide integrity or free-thiol reactivity, not merely RP-HPLC area percent; a peptide that is chromatographically pure but whose maleimide has hydrolysed will not conjugate to albumin and will behave like the short-acting form. Purity should be stated with a threshold and method, with endotoxin and aggregate data for any parenteral research use. Informational only.

08References and evidence

Primary sources

1. Prolonged Stimulation of Growth Hormone (GH) and Insulin-Like Growth Factor I Secretion by CJC-1295, a Long-Acting Analog of GH-Releasing Hormone, in Healthy Adultsclinical trialTeichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA — Journal of Clinical Endocrinology & Metabolism, 2006;91(3):799-805
2. Pulsatile Secretion of Growth Hormone (GH) Persists during Continuous Stimulation by CJC-1295, a Long-Acting GH-Releasing Hormone Analogclinical trialIonescu M, Frohman LA — Journal of Clinical Endocrinology & Metabolism, 2006;91(12):4792-4797
3. FDA Briefing Document, Pharmacy Compounding Advisory Committee (PCAC) Meeting - evaluation of CJC-1295, AOD-9604 and thymosin alpha-1 bulk drug substancesregulatoryU.S. Food and Drug Administration — FDA, 4 December 2024
4. CJC-1295 (tertiary source, used only for DAC linker description, development history and discontinuation narrative)tertiary sourceWikipedia contributors — Wikipedia, retrieved August 2026
5. NCATS Inxight Drugs - CJC-1295 (UNII 62RC32V9N7)regulatoryNational Center for Advancing Translational Sciences — NCATS Inxight Drugs, retrieved August 2026
6. The 2026 Prohibited List, International Standard - section S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics)regulatoryWorld Anti-Doping Agency — WADA, in force 1 January 2026

Chemical and molecular databases

• FDA compounding docket FDA-2024-N-4777-0002, attachment 7 - comparison table for CJC-1295 Modified GRF(1-29) vs CJC-1295 + DAC (sequence, MW 3647.15, half-lives ~30 min vs 6 days)
• ProSpec CJC-1295 DAC technical datasheet (manufacturer documentation - sequence, purity, reconstitution and storage only)
• ChemicalBook CAS 863288-34-0 - CJC-1295 without DAC / Modified GRF(1-29), C152H252N44O42, 3367.90 (supplier aggregator; illustrates the naming conflation)
• FDA - Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (Category 2)
• WADA Prohibited List landing page

09Related compounds

• CJC-1295 (no DAC)The identical tetrasubstituted GRF(1-29) core without the Lys30 maleimidopropionyl group - same pharmacology, half-life shorter by two to three orders of magnitude.Reference page in preparation
• SermorelinThe unmodified GHRH(1-29) parent peptide from which CJC-1295's four substitutions were derived.Reference page in preparation
• TesamorelinThe only GHRH(1-29) analogue to reach FDA approval, making it the direct regulatory and mechanistic benchmark for this class.
• IpamorelinActs on the complementary ghrelin receptor pathway and is the compound most frequently co-formulated with CJC-1295 in commerce.
• MK-677 (Ibutamoren)An orally active ghrelin receptor agonist offering long GH stimulation by the alternative receptor route, and listed alongside CJC-1295 by WADA.Reference page in preparation

10Frequently asked questions