CJC-1295 No DAC

CJC-1295 No DAC is a substituted analog of the first 29 residues of human growth hormone releasing factor, with an amidated C-terminus. It is also sold as modified growth hormone releasing factor 1 to 29. It shares its backbone with CJC-1295 with DAC but lacks the C-terminal lysine carrying a maleimide group, the drug affinity complex that lets the named compound bind albumin in circulation (Jetté et al., 2005).

That one difference separates two compounds with very different published records.

Public synonym lists for these compounds are not clean: the PubChem entry carrying CAS 863288-34-0 also lists names belonging to the version with DAC.

Most published work concerns either the native releasing factor fragment or the version with DAC. This guide keeps those apart and states the model for every finding.

Why the backbone is substituted

Native growth hormone releasing factor is cleaved at its amino terminus by a plasma dipeptidylaminopeptidase into a product with under one thousandth of the parent's activity (Frohman et al., 1986). Dipeptidyl peptidase IV does not cleave substrates that carry a D-configuration residue at that position (Bongers et al., 1992), and in healthy men a D-alanine at position 2 roughly halved metabolic clearance and extended the disappearance half-time from 4.3 to 6.7 minutes (Soule et al., 1994).

Asparagine deamidation at position 8 was the main route of degradation of an earlier analog in neutral aqueous solution (Friedman et al., 1991), which glutamine, a far slower-deamidating residue, largely avoids, and leucine at position 27 removes an oxidation-prone methionine. Models: human plasma in vitro, enzyme kinetics, healthy volunteers and aqueous stability studies.

The version with DAC

The named compound CJC-1295 came out of a bioconjugation program: maleimido derivatives of the 1 to 29 fragment conjugated to serum albumin resisted dipeptidyl peptidase IV and stayed active in cultured rat pituitary cells, and the lead derivative, CJC-1295, remained in rat plasma beyond 72 hours (Jetté et al., 2005).

In two placebo-controlled trials in healthy adults, that version raised mean growth hormone two to ten fold for six days or more, with an estimated half-life of 5.8 to 8.1 days (Teichman et al., 2006). Those figures belong to the albumin-binding version only. Models: rat cell culture, rats and healthy human adults.

The evidence gap for No DAC

A 2026 review of peptides acting on the growth hormone axis placed the form without the drug affinity complex in its lowest evidence tier: essentially uncharacterized in the peer-reviewed human literature, with no reported human half-life, its expected behavior inferred from the unmodified 1 to 29 fragment rather than measured (Dominikowski et al., 2026).

The substitutions above were chosen to slow the breakdown of a peptide cleared in minutes; the only one measured in people, D-alanine at position 2, extended the disappearance half-time from 4.3 to 6.7 minutes (Soule et al., 1994), and none of them produces the multi-day profile of the version with DAC. A study citing the 5.8 to 8.1 day half-life while using No DAC material is citing the wrong molecule.

Pairing with a secretagogue

Releasing factor analogs are often studied alongside secretagogues such as ipamorelin because the two act through separate receptors. In rat pituitary cell culture, a secretagogue and the releasing factor gave a synergistic effect on growth hormone release at maximal concentrations; only the releasing factor raised cyclic AMP, and the two did not cross-desensitize (Cheng et al., 1989). That is an in-vitro rationale for combination designs, not evidence of a combined outcome. Model: rat cell culture.