Research Overview
Both catalog items start from the same substituted analog of the first 29 residues of human growth hormone releasing factor. One chemical group separates them, and that group is the whole comparison: the drug affinity complex version carries a maleimide-bearing lysine at the C-terminus that bonds covalently to a free thiol on circulating albumin, adding roughly 279 g/mol and turning a peptide cleared in minutes into one measured in days.
The named compound CJC-1295 is the version with that group (Jette et al., Endocrinology 2005, PMID 15817669); the No DAC material is the same backbone without it, also sold as modified growth hormone releasing factor 1 to 29.
Structure and Class
The parent backbone is the native 1 to 29 fragment of human growth hormone releasing factor, in PubChem at C149H246N44O42S, approximately 3357.9 g/mol (CID 16132413). Both forms use a substituted version of that chain: the PubChem sequences show four changes against the native fragment, at position 2 (L-alanine to D-alanine), 8 (asparagine to glutamine), 15 (glycine to alanine) and 27 (methionine to leucine), with an amidated C-terminus.
Each substitution tracks a documented degradation route. The native releasing factor is cleaved at the amino terminus by a plasma dipeptidylaminopeptidase to a product with under one thousandth of parent activity (Frohman et al., J Clin Invest 1986, PMID 3093533), and dipeptidyl peptidase IV does not cleave substrates carrying a D-configuration residue there (Bongers et al., Biochim Biophys Acta 1992, PMID 1353684); in healthy men the D-alanine substitution cut metabolic clearance roughly in half and extended the disappearance half-time from 4.3 to 6.7 minutes (Soule et al., J Clin Endocrinol Metab 1994, PMID 7962295).
Asparagine deamidation at position 8 was the major aqueous degradation route of an earlier analog (Friedman et al., Int J Pept Protein Res 1991, PMID 1904406), so glutamine replaces it, and leucine at 27 removes the oxidation-prone methionine.
Identity data: No DAC is C152H252N44O42, approximately 3367.9 g/mol, CAS 863288-34-0, PubChem CID 56841945; the drug affinity complex is C165H269N47O46, printed as 3647.06 g/mol on its catalog page (CID 91971820, CAS 446262-90-4). The gap is the added lysine plus the maleimidopropionamide group, described in the original characterization as an N-epsilon-3-maleimidopropionamide derivative of lysine at the C-terminus (Jette et al., Endocrinology 2005, PMID 15817669). One warning: public synonym lists here are not clean, and the entry carrying CAS 863288-34-0 also lists aliases for the complex version. Identify material by formula, molecular weight and printed certificate identity.
Side by Side
| Attribute | CJC-1295 with DAC | CJC-1295 No DAC |
|---|---|---|
| Compound class | Substituted releasing factor 1 to 29 amide with a C-terminal maleimide group | Substituted releasing factor 1 to 29 amide, no conjugation group |
| Identity data | C165H269N47O46, approximately 3647 g/mol, CAS 446262-90-4 | C152H252N44O42, approximately 3367.9 g/mol, CAS 863288-34-0 |
| Mechanism of the difference | Maleimide reacts with a free thiol on serum albumin, forming a covalent bioconjugate | No conjugation chemistry; circulates unbound |
| Reported duration | Half-life 5.8 to 8.1 days in healthy adults; IGF-I elevated up to 28 days after repeated doses | Not reported in any peer-reviewed human study |
| Published human data | Two placebo-controlled dose-ascending trials plus a pulsatility study | None retrieved; review reports no peer-reviewed human studies |
| Supplied form | Lyophilized powder, single vial | Lyophilized powder, single vial, also in a blend with ipamorelin |
Research Context: The DAC Version
The original characterization is a chemistry paper with pharmacology attached. Three maleimido derivatives of the 1 to 29 fragment were conjugated to human serum albumin outside the body; all three resisted dipeptidylpeptidase-IV better than the parent and released growth hormone in cultured rat anterior pituitary cells. In rats, the best derivative gave a four fold increase in area under the curve over two hours, was still present in plasma beyond 72 hours, and appeared on a western blot at the serum albumin band from 15 minutes onward (Jette et al., Endocrinology 2005, PMID 15817669). Models: rat cell culture and rats.
Human pharmacodynamics were reported in two randomized placebo-controlled dose-ascending trials of 28 and 49 days. A single administration in these trials produced dose-dependent increases in mean plasma growth hormone of two to ten fold for six days or more and in IGF-I of 1.5 to three fold for nine to eleven days; the estimated half-life was 5.8 to 8.1 days, and IGF-I stayed above baseline up to 28 days after multiple administrations (Teichman et al., J Clin Endocrinol Metab 2006, PMID 16352683).
A separate study sampling overnight in healthy men a week after a single administration found pulsatility preserved, with trough growth hormone up about 7.5 fold (Ionescu et al., J Clin Endocrinol Metab 2006, PMID 17018654). Model: healthy human adults.
A knockout mouse study tested the interval directly: mice lacking the releasing hormone gene reached normal weight and length over five weeks on a 24-hour interval, while 48-hour and 72-hour intervals improved growth only partly (Alba et al., Am J Physiol Endocrinol Metab 2006, PMID 16822960).
The conjugate also behaves differently in the laboratory: it is hard to detect in blood by mass spectrometry because of low abundance, high molecular weight and conjugation to varied protein substrates, and one method paper reports confirmation in equine plasma only after immuno-affinity capture and tryptic digestion (Timms et al., Drug Test Anal 2019, PMID 30938069). Model: equine plasma.
Research Context: The No DAC Version
This is where the comparison gets short, and the shortness is the finding. A 2026 review of growth hormone axis peptides placed the form without the drug affinity complex in its lowest evidence tier: essentially uncharacterized in the peer-reviewed human literature, no reported human half-life, its expected effect inferred from the unmodified 1 to 29 fragment rather than measured (Dominikowski et al., Front Endocrinol 2026, PMID 42395176).
What can be said rests on backbone chemistry rather than studies of the finished compound, and those substitutions buy minutes to hours on a peptide cleared in minutes, not a multi-day profile. The two forms are therefore not two strengths of one compound: one has placebo-controlled human pharmacodynamic data and a measured half-life, the other a characterized structure and an inferred profile. A protocol citing the 5.8 to 8.1 day half-life while using No DAC material is citing the wrong molecule.
Choosing Between Them for a Research Question
Sustained-exposure questions point to the conjugating form: duration, albumin bioconjugate chemistry, exposure-interval effects, and anything needing a published human reference profile. Short-exposure questions point to the No DAC form: acute release, repeated short stimulations, and designs where a multi-day tail would confound the readout.
The same split applies to analytical work: the conjugate needs capture and digestion before confirmation (Timms et al., Drug Test Anal 2019, PMID 30938069), while the unconjugated analog is an ordinary 29-residue peptide for liquid chromatography and mass spectrometry. Whichever form a study uses, state it by formula and molecular weight rather than by name, since the two share a trade name and differ by about 279 g/mol.
Handling and Storage
Both forms ship lyophilized and are most stable dry, cold and dark. Keep the sealed vial cold until use, let it reach room temperature before opening so moisture does not condense onto the cake, add diluent slowly down the wall, and let the powder dissolve without shaking. The Disguised Alpha pages for both state minus 20 C for the powder as shipped and 2 to 8 C after reconstitution, protected from light, freeze-thaw avoided.
The maleimide group deserves specific care. Maleimides react with free thiols, which is the entire point of the complex, and they hydrolyze in aqueous solution over time, so a reconstituted conjugating peptide is reasonably treated as more time-limited than the unconjugated analog, and thiol-containing additives in a diluent are an obvious interference. For both forms, aliquot into single-use volumes, record the lot number, and take the molecular weight for molarity from the certificate.
Questions Researchers Ask
What does DAC actually mean?
A reactive maleimide group on a lysine added at the C-terminus. It bonds covalently to a free thiol on circulating serum albumin, so the peptide travels bound to a large plasma protein instead of clearing quickly (Jette et al., Endocrinology 2005, PMID 15817669).
Is the No DAC form just a weaker version?
No, a shorter-lived one, and far less characterized. The published half-life of 5.8 to 8.1 days belongs to the albumin-binding version (Teichman et al., J Clin Endocrinol Metab 2006, PMID 16352683), while a 2026 review states the form without the complex has no peer-reviewed human studies and no reported human half-life (Dominikowski et al., Front Endocrinol 2026, PMID 42395176).
Why are the four backbone substitutions there?
Each addresses a documented degradation route of the native releasing factor: amino-terminal cleavage by a plasma dipeptidyl peptidase (Frohman et al., J Clin Invest 1986, PMID 3093533; Bongers et al., Biochim Biophys Acta 1992, PMID 1353684; Soule et al., J Clin Endocrinol Metab 1994, PMID 7962295), asparagine deamidation in aqueous solution (Friedman et al., Int J Pept Protein Res 1991, PMID 1904406), and an oxidation-prone methionine.
Does sustained stimulation remove the natural rhythm of release?
In the one study that measured it, no: overnight sampling in healthy men a week after a single administration of the albumin-binding version found pulse frequency and magnitude unchanged, with trough and mean levels raised (Ionescu et al., J Clin Endocrinol Metab 2006, PMID 17018654).
Both CJC-1295 forms are supplied strictly for laboratory and in-vitro research use. They are not for human consumption, veterinary use, or any diagnostic or therapeutic application. Nothing on this page is medical, dosing, or therapeutic advice.