A calm research digest · long-acting GHRH analog
CJC-1295 is a long-acting GHRH analog studied for the aging growth-hormone and IGF-1 axis.
A tactile reading of the published record — what the pharmacokinetic studies measured, where the human data stop, and how the longevity framing lines up against the literature.
What CJC-1295 is, in one reading
CJC-1295 is a synthetic long-acting analog of growth-hormone-releasing hormone (GHRH) — the hypothalamic signal that tells the pituitary to make and release growth hormone. It is built on the first 29 amino acids of human growth-hormone-releasing factor, hGRF(1-29), and carries four substitutions (D-Ala at position 2, Gln at 8, Ala at 15, Leu at 27) that stabilize the molecule and block the enzymes that would otherwise chew it up in minutes [2][11]. In the DAC variant, a chemical handle lets the peptide bind covalently to circulating serum albumin, and that bond is what stretches its half-life from minutes to days [2][10].
The headline finding is precise. In healthy adults, single subcutaneous doses of 30 or 60 micrograms per kilogram raised mean plasma growth hormone 2- to 10-fold for six days or more and IGF-1 for nine to eleven days, with an estimated half-life of 5.8 to 8.1 days [1]. That is the whole character of the compound in one sentence: slow, smooth, sustained. This site reads that record carefully — what the research shows, the research doses studied, and the open questions — and is candid about a second fact: CJC-1295 is an unapproved research chemical, not a treatment.
The single most confused point in the literature is the difference between the two forms, so it gets its own page: CJC-1295 DAC vs no-DAC. The DAC form is the multi-day one. The no-DAC form, often sold as Modified GRF (1-29), is short-acting. They are frequently conflated and they are pharmacokinetically very different.
CJC-1295 peptide: structure and class
The CJC-1295 peptide is a GHRH-analog peptide, not a steroid and not a hormone replacement. Its backbone is hGRF(1-29), the minimal fragment of human GHRH that keeps full growth-hormone-releasing activity. Onto that backbone sit the four protease-resistant substitutions; the DAC variant adds the albumin-binding moiety [2].
The registry data is plain fine print. The molecular weight of the DAC peptide before albumin conjugation is reported at roughly 3,368 daltons, with CAS number 863288-34-0 and PubChem CID 91971820 — though registry sources disagree on the exact molecular formula, so the precise figure is one a careful reader should confirm. After the albumin bond forms, the species actually circulating in blood is the much larger peptide-albumin complex, near 66 kilodaltons. That size change is the engineering trick behind the long half-life.
What does CJC-1295 do?
In studied species, CJC-1295 binds the GHRH receptor on the pituitary's somatotroph cells and stimulates pulsatile growth-hormone release, which in turn raises liver-produced IGF-1 [1][3]. The mechanism is the same one the body uses with its own GHRH — CJC-1295 simply lasts far longer.
A notable detail kept the field interested. In healthy men, a single dose raised basal growth hormone roughly 7.5-fold and mean growth hormone about 46% one week later, yet the natural pulse-by-pulse pattern of secretion was unchanged [3]. Sustained stimulation did not flatten the rhythm. The natural pulsatility was preserved.
The honest counterweight sits right beside that finding. The long-acting DAC development program was discontinued, no controlled longevity trial of CJC-1295 itself exists, and the compound is prohibited at all times in sport under the World Anti-Doping Agency's peptide-hormone category [6]. The common questions about CJC-1295 page covers the compound's regulatory and anti-doping status directly.
Where the human data stop
The longevity and anti-aging interest around CJC-1295 is real, and it has a coherent rationale: the GH/IGF-1 axis declines with age — a phenomenon called somatopause — and modulating it has been proposed as a strategy against age-related muscle loss [8]. Related GHRH-class work has touched wound healing [9] and bone and skin endpoints in aged animals [10]. That is the honest case for studying the axis.
The honest limit is just as important. There is no controlled longevity trial of CJC-1295 itself. The human record is short-term pharmacokinetic work, the long-acting DAC development program was discontinued, and recent reviews situate the GHRH-analog class in the research conversation rather than the evidence base [13]. This digest holds both facts at once: a mechanistically interesting compound, and a thin human record. Neither cancels the other.
How to use this digest
Four pages carry the substance. What the research shows walks the mechanism, the human pharmacokinetic studies, the CJC-1295 and ipamorelin synergy rationale, the body-composition framing, and the safety picture. CJC-1295 DAC vs no-DAC is the side-by-side on the two forms, including Modified GRF (1-29). CJC-1295 half life is the pharmacokinetics in detail. The research doses studied page reports only what was administered in published work — never a recommendation.
Every quantitative claim on this site maps to a numbered entry in the study references. Where the literature is precise, the numbers are precise. Where it is thin — and on long-term human safety it is thin — the digest says so plainly rather than filling the gap.