CJC-1295 vs Mod-GRF (1-29).

CJC-1295 is a synthetic analog of growth hormone-releasing hormone (GHRH), based on the first 29 amino acids of human GHRH (GRF 1-29) with several amino-acid substitutions that resist enzymatic degradation. The name is used for two distinct molecules: "CJC-1295 with DAC," which carries a Drug Affinity Complex (a maleimidoproprionic acid linker) that covalently binds to circulating albumin to dramatically prolong its action; and "CJC-1295 without DAC" (often sold as "modified GRF 1-29" or "Mod GRF 1-29"), which lacks the albumin-binding linker. It was originally developed by the Canadian biotech company ConjuChem as an investigational therapeutic.

Mod GRF 1-29 (commonly sold as "CJC-1295 without DAC") is a synthetic 29-amino-acid analog of growth hormone-releasing hormone (GHRH). It is the same tetra-substituted GHRH(1-29) peptide backbone used in CJC-1295, but it lacks the maleimido "Drug Affinity Complex" (DAC) linker that the long-acting form carries, so it behaves as a short-acting GHRH secretagogue. Its parent fragment, native GHRH(1-29) ("sermorelin"), retains essentially the full GH-releasing activity of the 44-residue hormone, and the four engineered substitutions are added to slow enzymatic breakdown.

As a GHRH analog, CJC-1295 binds the GHRH receptor on somatotroph cells of the anterior pituitary, activating Gs-protein/cAMP/PKA signaling to stimulate synthesis and pulsatile release of endogenous growth hormone (GH), which in turn raises hepatic insulin-like growth factor 1 (IGF-1). The four substitutions in the GRF(1-29) backbone (notably at the position-2 alanine that is the dipeptidyl peptidase-IV cleavage site) protect the peptide from rapid breakdown, extending the half-life of the non-DAC form to roughly 30 minutes versus minutes for native GHRH. In the DAC version, the maleimide linker forms a covalent bond with cysteine-34 of serum albumin, creating a long-circulating depot; because it raises GH in a more sustained rather than sharply pulsatile manner, it is described as increasing trough and mean GH while largely preserving the body's own pulse pattern.

Like endogenous GHRH, the peptide binds the GHRH receptor on anterior-pituitary somatotrophs, raising intracellular cAMP and triggering pulsatile synthesis and release of growth hormone, which in turn drives hepatic IGF-1 production. The four amino-acid substitutions relative to native GHRH(1-29), typically described as D-Ala at position 2, Gln8, Ala15, and Leu27, are intended to resist degradation, with the D-alanine substitution at position 2 specifically blocking cleavage by dipeptidyl peptidase-IV (DPP-IV), the main enzyme that rapidly inactivates GHRH. Because it has no albumin-binding DAC tether, it is cleared quickly and is described as producing brief, pulse-like GH stimulation rather than the sustained "GH bleed" seen with the DAC version. It is mechanistically a secretagogue: it prompts the pituitary's own GH, rather than supplying GH directly.

The principal human evidence is a single 2006 Phase 1 study in healthy adults by Teichman et al. (J Clin Endocrinol Metab, PMID 16352683), which reported that one subcutaneous dose of CJC-1295 with DAC produced dose-dependent increases in mean plasma GH of roughly 2- to 10-fold for 6 days or more and IGF-1 increases of about 1.5- to 3-fold for 9-11 days, with an estimated half-life of 5.8-8.1 days and IGF-1 staying above baseline up to 28 days after repeated dosing. ConjuChem advanced the DAC compound into a Phase 2 trial in HIV-associated visceral obesity (ClinicalTrials.gov NCT00267527), but that 12-week trial was terminated in 2006. Beyond these, robust controlled human efficacy and long-term safety data are essentially absent; there are no large or long-term trials, no published outcomes for the non-DAC "modified GRF 1-29" form in humans, and much of the mechanistic rationale rests on GHRH-class pharmacology rather than direct trials of this molecule. Claims about body composition, recovery, or anti-aging benefit are not supported by published controlled human outcome data.

The well-known human trials in this family, Teichman et al. (JCEM, 2006), Ionescu & Frohman (JCEM, 2006), and Sackmann-Sala et al. (Growth Horm IGF Res, 2009), all studied CJC-1295 WITH DAC, the long-acting albumin-binding version, not the no-DAC Mod GRF 1-29; Alba et al. (2006) used a GHRH-knockout mouse model. There is no robust, peer-reviewed human clinical trial of Mod GRF 1-29 (the no-DAC peptide) under that name establishing efficacy or safety, so claims about it are largely inferred from GHRH/sermorelin pharmacology and from the DAC-form data rather than directly tested. The unmodified parent peptide, sermorelin/GHRH(1-29), was an FDA-approved diagnostic and pediatric GH agent and is the best-characterized human reference point. Most published mentions of the no-DAC compound itself come from anti-doping analytical chemistry (e.g., Henninge et al., Drug Test Anal, 2010, identifying CJC-1295 in an illicit preparation), which characterize the molecule but not its clinical effects. Honest bottom line: the human-versus-preclinical gap is wide here, and the short-acting form is plausible by analogy but essentially unproven in controlled human studies.

In the short Phase 1 work, CJC-1295 with DAC was described as generally well tolerated, with the kinds of effects expected from GHRH-class agents (e.g., injection-site reactions, flushing, headache); however, this reflects small numbers and short follow-up. The Phase 2 HIV trial (NCT00267527) was terminated in 2006, and a participant death during the program drew scrutiny, though available reporting attributed that death to pre-existing coronary disease rather than establishing causation by the drug; the episode underscores how thin the safety record is. Sustained elevation of GH/IGF-1 carries class-level theoretical concerns familiar from growth-hormone pharmacology, including fluid retention, joint/muscle pain, insulin resistance and elevated blood glucose, and a theoretical concern about promoting growth of existing malignancy; long-term safety in humans is simply unknown. Much material sold as "CJC-1295" online is from unregulated sources with no purity, sterility, or identity guarantees, adding contamination and mislabeling risks.

Documented safety data specific to Mod GRF 1-29 are minimal because controlled human trials of the no-DAC peptide are lacking; what is known is extrapolated from GHRH analogs broadly. In studies of related GHRH analogs and sermorelin, injection-site reactions (redness, swelling), flushing, and headache are the most commonly reported effects, and any sustained elevation of the GH/IGF-1 axis carries theoretical concerns including fluid retention, joint discomfort, insulin resistance/altered glucose handling, and uncertainty about long-term proliferative risk because IGF-1 is mitogenic. A major real-world hazard is that material sold under this name is research-grade and unregulated, so purity, identity, sterility, and contamination are not assured; anti-doping case reports document the compound appearing in mislabeled or "unknown" pharmaceutical preparations. Interactions with somatostatin tone, other secretagogues, and underlying endocrine or oncologic conditions are not well characterized, and long-term human safety is simply unknown.

CJC-1295 (with or without DAC) has never been approved by the FDA or any major regulatory agency for any indication and remains an investigational compound that did not complete clinical development. It is not an approved medicine; it is sold only as a "research chemical," and GHRH analogs/GH secretagogues of this type are prohibited in sport by the World Anti-Doping Agency.

Mod GRF 1-29 / CJC-1295 without DAC is not approved by the FDA or any major regulator for any indication and is an investigational/research-use-only compound; its unmodified parent, sermorelin, was previously FDA-approved but has been commercially discontinued. As a GHRH analog it falls under the World Anti-Doping Agency (WADA) Prohibited List class S2 (peptide hormones / growth factors and related substances) and is banned in sport at all times.