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CJC-1295 half-life is the defining property of this long-acting GHRH analog, and the focus of the research overview below.
CJC-1295 is studied as a model for how peptide engineering can extend half-life. We look at the albumin-binding chemistry behind its long duration and what pharmacokinetic research suggests about its sustained activity on the growth hormone axis.
CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH), built on the first 29 amino acids of human GHRH, known as GRF(1-29). Native GHRH has a very short circulating half-life, on the order of minutes, which has historically limited its research utility. CJC-1295 was designed to address that limitation directly, which makes it a useful case study in peptide half-life research.
Research describes two distinct design features working together. First, the GRF(1-29) backbone carries amino acid substitutions that make it more resistant to breakdown by dipeptidyl peptidase IV (DPP-IV), an enzyme that rapidly inactivates native GHRH. Second, the version commonly studied with a drug affinity complex (DAC) carries a reactive group that covalently bonds to circulating serum albumin after administration. Because albumin itself has a long circulating life, the bound peptide is reported to remain in circulation far longer than the unmodified sequence.
Reported to have a very short circulating half-life, measured in minutes, due to rapid enzymatic degradation.
Amino acid substitutions improve in vitro stability against DPP-IV, extending activity relative to native GHRH.
Covalent albumin binding has been reported to extend the estimated half-life to several days in human studies.
Albumin bioconjugates retained the ability to activate the GRF receptor and stimulate GH secretion in preclinical assays.
In a randomized, placebo-controlled study in healthy adults, a single subcutaneous administration of CJC-1295 was associated with the pharmacokinetic and pharmacodynamic observations summarized below. We present these as reported research findings.
| Parameter Studied | Reported Observation |
|---|---|
| Estimated half-life | Approximately 5.8 to 8.1 days |
| Mean plasma GH | Increased 2 to 10-fold for 6 days or more |
| Mean plasma IGF-1 | Increased 1.5 to 3-fold for 9 to 11 days |
| IGF-1 after multiple doses | Remained above baseline for up to 28 days |
Animal work has examined how administration frequency interacts with the extended half-life. In a GHRH knockout mouse model, CJC-1295 given at 24-hour intervals was reported to support normal body weight and length, while the same dose spaced at 48 or 72-hour intervals was less effective. This illustrates that an extended half-life and the practical dosing interval are related but distinct research variables.
For peptide half-life research, CJC-1295 is a clear illustration of how targeted structural changes, enzymatic resistance plus albumin conjugation, can transform the pharmacokinetic profile of a short-lived signaling peptide. We share this material strictly for its scientific and laboratory interest.
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