A research overview of the CJC-1295 peptide: GHRH-analogue mechanism, the DAC albumin-binding chemistry, what the 2006 human trials measured, and why development stopped.
CJC-1295 is a synthetic analogue of the first 29 residues of growth-hormone-releasing hormone — the minimal fragment that retains full activity at the GHRH receptor — carrying four amino-acid substitutions that block enzymatic degradation. It is one of the few peptides in this catalogue with published, placebo-controlled human pharmacokinetic and pharmacodynamic data, and also one of the few whose clinical development was halted outright. Both facts matter when reading the compound.
A complication before anything else: two different molecules circulate under the name. CJC-1295 with DAC is the original ConjuChem compound, engineered to bind serum albumin and circulate for days. CJC-1295 without DAC — properly modified GRF (1-29) — is the same peptide backbone without the albumin-binding group, with a plasma half-life on the order of half an hour. The published human data described below is with-DAC data. That distinction is covered in depth in CJC-1295 — with DAC or without?.
The GHRH receptor sits on anterior-pituitary somatotrophs. Binding drives GH synthesis and release, and the system remains under somatostatin negative feedback — the structural argument that separates every GHRH analogue from exogenous HGH, where no such brake exists.
Native GHRH(1-29) is cleaved within minutes by dipeptidyl peptidase-4 and other plasma proteases. CJC-1295 substitutes four residues (D-Ala at position 2, Gln at 8, Ala at 15, Leu at 27) to resist that cleavage while retaining receptor affinity. That alone yields modified GRF (1-29).
The DAC — Drug Affinity Complex — is a separate piece of engineering bolted onto the C-terminus: a lysine bearing a maleimidopropionyl group. After subcutaneous injection the maleimide reacts with the free thiol at cysteine-34 of circulating human serum albumin, the only unpaired cysteine on the protein, forming a stable covalent thioether bond. The peptide then inherits albumin's pharmacokinetics — shielded from renal filtration and proteolysis, circulating for days rather than minutes.
Two studies from the ConjuChem program, both published in the Journal of Clinical Endocrinology & Metabolism in 2006, carry essentially the entire human record.
Teichman et al. (2006) ran two randomised, placebo-controlled, double-blind ascending-dose trials in healthy adults aged 21–61. Single subcutaneous doses produced dose-dependent increases in mean plasma GH of 2- to 10-fold sustained for six days or longer, and in mean plasma IGF-I of 1.5- to 3-fold for nine to eleven days. Estimated half-life was 5.8 to 8.1 days. After repeated weekly or biweekly dosing, IGF-I remained above baseline for up to 28 days, with evidence of accumulation. Tolerability was reported as acceptable, particularly at 30 and 60 µg/kg.
Ionescu and Frohman (2006) asked the more interesting question: does continuous receptor stimulation flatten GH secretion into a tonic signal? Healthy men aged 20–40 received a single 60 or 90 µg/kg dose, with 12-hour overnight sampling before and one week after. Pulse frequency and pulse amplitude were unaltered. What rose was the floor: basal GH increased roughly 7.5-fold, carrying mean GH up about 46% and IGF-I about 45%. The authors attributed the IGF-I rise specifically to elevated trough GH.
That result inverts a common marketing claim. CJC-1295 with DAC does not amplify the natural pulse; it raises the space between pulses — a sustained low-grade GH elevation superimposed on unchanged pulse architecture. That is a departure from physiological GH secretion, not a restoration of it.
ConjuChem carried CJC-1295 into a Phase II trial in HIV-associated lipodystrophy enrolling 192 participants. In July 2006, roughly a month from completion, the study was halted following the death of a participant at a site in Argentina. The cause and any relationship to the study drug were under investigation at the time and were never established in the public record as drug-attributable; the program nonetheless did not advance to Phase III, and the company later wound down without a successor sponsor pursuing registration.
The honest reading is narrow. A halted trial with a single unadjudicated event is not evidence the compound caused harm — but it is also not the clean safety record sometimes implied, and it is why there is no approved label, no long-term exposure dataset, and no post-marketing surveillance here. Tesamorelin, a GHRH analogue whose lipodystrophy trials continued through the same period, went on to FDA approval — see the Tesamorelin research overview.
Against tesamorelin: same receptor, same endogenous-pulse logic, but tesamorelin has an approved indication, a short half-life, and daily dosing, versus CJC-1295 with DAC's multi-day exposure and no approval.
Against the ghrelin-receptor agonists — ipamorelin and the GHRPs — the axis is different entirely, which is the pharmacological rationale behind the combination format. See Ipamorelin vs CJC-1295 and the growth-hormone secretagogue category guide.
Catalogue references: CJC-1295 no DAC, CJC-1295 with DAC, and the CJC-1295 + Ipamorelin blend. Reconstitution and concentration figures are in CJC-1295 dosage — research dosing notes.
The entire human dataset is two small healthy-volunteer studies from a single sponsor, published twenty years ago, with no independent replication and no long-duration follow-up. Sustained IGF-I elevation over months or years has no characterised safety profile in this compound, and the with-DAC and without-DAC forms should not be treated as interchangeable in any reading of that literature.
CJC-1295 is also prohibited in sport at all times under section S2 of the WADA Prohibited List, where it is named explicitly among GHRH analogues.
Is CJC-1295 the same as modified GRF (1-29)? Not quite. Modified GRF (1-29) is the tetrasubstituted peptide backbone. CJC-1295 with DAC is that backbone plus the albumin-binding group. Vendors commonly sell the backbone alone as "CJC-1295 no DAC," which is why the half-life figures quoted for the name range from about 30 minutes to about a week.
What is the published half-life? 5.8 to 8.1 days for the DAC form, per Teichman et al. (2006). The no-DAC form is reported at roughly 30 minutes and has no comparable published human PK study of its own.
Does it preserve natural GH pulsatility? Pulse frequency and amplitude were unchanged in the Ionescu and Frohman data — but trough GH rose about 7.5-fold. Pulsatility persists; it sits on a raised baseline. Calling that "natural" overstates it.
Why was development discontinued? A Phase II lipodystrophy trial was halted in July 2006 after a participant death. Causality was never publicly established, and the sponsor did not carry the program forward to Phase III.
Is CJC-1295 approved anywhere? No. There is no approved indication, no approved label, and no regulator-reviewed safety dataset for ongoing administration.
