# CJC-1295 With DAC vs No DAC: What Is the Difference?

CJC-1295 with DAC and CJC-1295 no DAC are two different molecules, not two grades of one. The DAC form carries a maleimide group built to latch on to albumin in blood; no-DAC material, usually sold as Modified GRF (1-29), has no such group. This guide sets out the chemistry, the naming confusion in the public databases, and why the widely quoted multi-day half-life belongs to only one of them. Supplied for in vitro research purposes only.

- Source: https://www.australianresearchpeptides.au/articles/cjc-1295-dac-vs-no-dac
- Reading time: 10 minute read
- Published: 2026-09-02
- Publisher: Australian Research Peptides

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## What Is the Difference Between CJC-1295 With DAC and No DAC?

CJC-1295 with DAC carries an extra chemical group designed to latch on to a blood protein, so it persists for days. Material sold as CJC-1295 no DAC has no such group. They are two different molecules with almost the same name.

The confusion is not the buyer’s fault. Both forms are built on the same 29-amino-acid backbone, both are sold under the label CJC-1295, and the published human evidence describes only one of them. The table below is the short answer; the sections after it show how each row can be checked.

_CJC-1295 with DAC compared against CJC-1295 no DAC, by chemistry, naming and the published record_

|  | CJC-1295 with DAC | CJC-1295 no DAC |
| --- | --- | --- |
| Chain length | 30 amino acids — a lysine added at the tail | 29 amino acids |
| The DAC group | Present. A maleimide group on that added lysine | Absent |
| Also called | DAC:GRF, CJC-1295 DAC | Modified GRF (1-29), Mod GRF 1-29 |
| Formula on PubChem | C165H269N47O46, MW 3647.2 | C152H252N44O42, MW 3367.9 |
| Human half-life reported | 5.8–8.1 days, in one 2006 study | None established in the papers cited here |
| What ARP lists | Not listed | The no-DAC form, blended with ipamorelin |

## What Does DAC Mean in CJC-1295?

DAC stands for Drug Affinity Complex. It is a maleimide-containing group bolted to the end of the peptide, and its job is to react with a single sulfur atom on a protein already circulating in blood. That reaction is the whole persistence strategy.

The target is cysteine-34 on serum albumin. Albumin is the most abundant protein in blood plasma, and cysteine-34 is the one position on it carrying a free thiol — a sulfur-hydrogen pair reactive enough to form a bond. A maleimide group is chosen because it reacts with such thiols quickly and selectively.

Jetté and colleagues described exactly this in 2005. They synthesised three maleimide derivatives of human GRF(1-29), joined them to human serum albumin outside the body, and reported that all three stayed active in a growth-hormone secretion assay using cultured rat pituitary cells. Their best compound was named CJC-1295: a tetrasubstituted GRF(1-29) — four of its amino acids swapped for others — with an added lysine at the tail carrying a 3-maleimidopropionamide group.

The added group is the product name.

Take the DAC group away and the molecule that remains is not a weaker CJC-1295. It is the tetrasubstituted 29-amino-acid peptide the DAC was attached to, which the literature calls Modified GRF (1-29).

## Why Bind to Albumin at All?

Albumin binding buys time. A small peptide is cleared from blood within minutes, partly by filtration at the kidney and partly by enzymes. Albumin is large, long-lived and not filtered, so a peptide riding on it is shielded from both routes.

The enzyme that matters most here is dipeptidyl peptidase-IV, which clips two amino acids off the front of GHRH-family peptides. The 2005 work reported that the albumin conjugates — the peptide joined to albumin — showed enhanced stability against it in vitro, meaning in glassware rather than in a living subject. Note the wording: the paper reports improved stability, not immunity. That is the second half of the design, the albumin attachment slowing clearance while the backbone substitutions slow the enzyme.

Chapter and colleagues place this in its wider setting. Their 2010 review of chemical modification of class II receptor ligands treats albumin conjugation as one of a family of strategies for making short-lived neuroendocrine peptides last. Amino-acid substitution and fatty-acid attachment are two of the others.

## What Did the Human CJC-1295 Study Report?

Teichman and colleagues reported an estimated half-life for CJC-1295 of 5.8 to 8.1 days in healthy adults in 2006. That figure describes the DAC form and nothing else, and it is the single most quoted number in this whole subject.

The study was two randomised, placebo-controlled, double-blind ascending trials, of 28 and 49 days, in healthy adults aged 21 to 61. After a single subcutaneous injection, mean plasma growth hormone rose two- to ten-fold for six days or more, and mean IGF-I rose 1.5- to three-fold for nine to eleven days. After repeated injections, mean IGF-I stayed above baseline for as long as 28 days. No serious adverse reactions were reported.

Read the molecule, not just the number.

The days-long duration is what the DAC group was built to produce. Quoting it beside a no-DAC product transfers a result from a molecule the vial does not contain.

## Is CJC-1295 No DAC the Same Molecule?

No. CJC-1295 no DAC is a different molecule from CJC-1295 with DAC, not a different preparation of one molecule. The two differ by one whole amino acid and one attached chemical group, and the difference is visible in the molecular formula.

PubChem publishes both. The no-DAC structure is C152H252N44O42 at 3367.9, and the DAC-bearing structure is C165H269N47O46 at 3647.2. Subtracting one from the other leaves C13H17N3O4.

That remainder is not an approximation. One lysine residue — one amino-acid unit inside a chain — is C6H12N2O and one 3-maleimidopropionyl group is C7H5NO3; added together they are exactly C13H17N3O4, weighing 128.17 and 151.12 for a total of 279.29. Add that to 3367.9 and the result is 3647.2, which is the published weight of the DAC form to the decimal. The arithmetic can be repeated from the two database pages in under a minute.

## One Database Record Carries Both Names

PubChem record CID 56841945 holds the structure of the no-DAC peptide while simultaneously listing “CJC 1295 with DAC” among its names. One record, two molecules, and it is the clearest illustration available of why a product name proves nothing about a structure.

The record was read directly from PubChem’s programmatic interface on 2 September 2026. Its structure fields describe a chain of 29 residues ending in argininamide, formula C152H252N44O42, weight 3367.9. Its InChIKey, the fingerprint string a structure hashes to, is XOZMWINMZMMOBR-HRDSVTNWSA-N. There is no maleimide in that structure and no thirtieth residue. Its synonym list, however, contains all of the following.

_Conflicting synonyms carried by a single PubChem record, and what each one actually refers to_

| Synonym on the record | What that name refers to |
| --- | --- |
| CJC-1295-no DAC acetate | The no-DAC form — which is what the record’s structure actually is |
| CJC 1295 with DAC | The DAC form — a different molecule, 30 residues |
| DAC:GRF acetate | The DAC form again, under its research name |
| 863288-34-0 and 446036-97-1 | Two different CAS registry numbers on one record |
| A 30-residue maleimide sequence string | A written-out DAC structure, one residue longer than the record’s own |

The last row is the sharpest of the five. The record carries a sequence string of thirty letters whose final lysine bears a maleimidopropionyl group, sitting beside a structure of twenty-nine residues that has neither. A reader who searches PubChem for CJC-1295 by name is sent somewhere else again, to record CID 91971820, which does hold the 30-residue DAC form under a third CAS number.

A name is not an identity.

Formula, molecular weight and sequence are checkable; a label on a listing or a synonym in a database is not. That is the same reasoning behind reading a certificate rather than a product title, worked through in

[how to read a certificate of analysis](https://www.australianresearchpeptides.au/articles/peptide-testing-purity-coa)

.

## Is Modified GRF (1-29) the Same as Natural GHRH (1-29)?

Modified GRF (1-29) is related to natural GHRH (1-29) but is not identical to it. Four of the twenty-nine positions have been swapped deliberately, which is what the word modified is recording, and the substitutions can be read straight off the public structures.

Aligning PubChem’s systematic name for the no-DAC peptide against its systematic name for sermorelin — the pharmaceutical form of GHRH (1-29) — puts the four differences at positions 2, 8, 15 and 27.

_The four substituted positions in Modified GRF (1-29) compared with natural GHRH (1-29)_

| Position | GHRH (1-29) | Modified GRF (1-29) |
| --- | --- | --- |
| 2 | Alanine | D-alanine — the mirror-image form of the same amino acid |
| 8 | Asparagine | Glutamine |
| 15 | Glycine | Alanine |
| 27 | Methionine | Leucine |

The last swap leaves a fingerprint anyone can check. Methionine is the only sulfur-carrying amino acid in GHRH (1-29), so sermorelin’s formula ends in an S — C149H246N44O42S. Replace it with leucine and the sulfur disappears, which is why the modified peptide’s formula has none.

The two formulas differ by C3H6 gained and one sulfur lost, which is all four substitutions together and not the position 27 swap on its own. Three of the four add a single CH2 each — asparagine to glutamine, glycine to alanine, methionine to leucine — while the D-alanine at position 2 is the mirror image of the alanine it replaces and changes no atom count at all. The net result is ten units heavier: 3367.9 against sermorelin’s 3357.9.

Position 2 is the one that changes behaviour most. Dipeptidyl peptidase-IV clips the first two residues off this family of peptides, and a D-amino acid there is not the shape the enzyme is built to cut. That is a general property of D-amino acid substitution rather than a measurement on this peptide; the 2010 review lists it among the modification strategies used across this receptor family. The swap at 27 removes the molecule’s only sulfur atom, which is checkable from the two formulas above. How sequence differences of this size change a molecule’s identity is covered in [peptide types, categories and blends](https://www.australianresearchpeptides.au/articles/peptide-types-categories-blends).

## Does CJC-1295 No DAC Have a Published Half-Life?

No verified human half-life for supplier-labelled Modified GRF (1-29) is established by any of the papers cited on this page. Numbers of around thirty minutes circulate widely on retail sites, and none of the sources listed below supports one.

This is a gap in the evidence rather than a secret. CJC-1295 with DAC was taken into human trials by its developer and Modified GRF (1-29) was not. So one form has a published profile of how it is absorbed and cleared, and the other does not. Anyone quoting a duration for no-DAC material should be asked which study measured it, in which species, and in how many subjects.

The boundary, stated plainly.

The 5.8 to 8.1 day figure belongs to the DAC form. It may not be applied to no-DAC material, and this page does not apply it.

## Where Does Ipamorelin Fit?

Ipamorelin is not a GHRH analogue at all, so the DAC question does not arise for it. An analogue is a molecule built on the structure of another; ipamorelin is built on nothing of the sort. It is a growth hormone secretagogue — a compound that prompts a gland to release something it already makes — and it is five amino acids long, acting at a different receptor from the one CJC-1295 acts on. There is no DAC version of ipamorelin.

Raun and colleagues characterised it in 1998, describing it as the first selective growth hormone secretagogue. Working in cultured rat pituitary cells, in rats and in conscious swine, they used receptor antagonists to establish that it releases growth hormone through a GHRP-like receptor rather than the GHRH receptor. In swine it did not raise ACTH or cortisol above the levels seen after GHRH stimulation.

That receptor difference is the reason the two peptides are studied as a pair rather than as substitutes. They reach the same gland by separate routes.

## Which Form Does ARP List?

Australian Research Peptides lists the no-DAC form, blended with ipamorelin in a single vial as [CJC-1295 (no DAC) + Ipamorelin](https://www.australianresearchpeptides.au/products/cjc-1295-ipamorelin) at 10 mg, currently available to order. There is no DAC-modified listing in the catalogue.

_What the blended vial contains, by component and nominal amount_

| Component | Nominal amount | Note |
| --- | --- | --- |
| CJC-1295 (no DAC) | ~5 mg | no DAC — not the DAC-modified analogue; also catalogued as Modified GRF (1-29) |
| Ipamorelin | ~5 mg | Not stated |

A batch certificate is published for this vial, and it reports identity and amount rather than a single purity percentage. That is normal for a multi-component vial: one figure cannot describe two peptides, so the laboratory reports each component instead. Certificates are listed in the [certificate library](https://www.australianresearchpeptides.au/coa), which shows the current state for every product and strength. The laboratory’s own name is printed on each document.

Ipamorelin is also catalogued on its own as [a single-peptide listing](https://www.australianresearchpeptides.au/products/ipamorelin), for anyone comparing a blend against separate vials. Everything on this page is supplied for in vitro research purposes only.

## Claim, Evidence and Boundary

The load-bearing statements on this page are set out below with the evidence behind them and the limit of what that evidence covers. Where a sentence elsewhere on the page states general peptide chemistry rather than a result from one of these sources, it says so in place.

_Each claim made on this page, the evidence supporting it, and the boundary of that evidence_

| Claim | Evidence | Boundary |
| --- | --- | --- |
| DAC is a maleimide group targeting cysteine-34 on albumin | Jetté 2005, which describes the strategy and names the site | Conjugation was done outside the body; activity was measured in cultured rat pituitary cells and in rats |
| A 5.8–8.1 day half-life was estimated in humans | Teichman 2006, in healthy adults | The DAC form only. It says nothing about no-DAC material |
| The two forms differ by one residue and one group | PubChem CID 56841945 and CID 91971820, formulas and weights read from the database | A structural statement about published records, not about any particular vial |
| One PubChem record carries names for both forms | CID 56841945 synonyms, read 2 September 2026 | Database records are curated and can change. Re-check before relying on it |
| Ipamorelin acts through a different receptor | Raun 1998, using GHRP and GHRH antagonists | Cultured rat pituitary cells, rats and swine. Not a human finding |
| No published human half-life for no-DAC material | Absence across the four sources listed below | An absence in these sources, not proof that no measurement exists anywhere |

## Related Guides

- [Tesamorelin: a GHRH analogue explainedAnother modified GHRH peptide, and what its trials actually measured.](https://www.australianresearchpeptides.au/articles/tesamorelin-ghrh-analogue-research)
- [Peptide testing, purity & CoAsHow a certificate establishes what is in a vial, and what it leaves unanswered.](https://www.australianresearchpeptides.au/articles/peptide-testing-purity-coa)
- [Peptide types, categories & blendsWhy one changed amino acid makes a different molecule, and how a blend is stated.](https://www.australianresearchpeptides.au/articles/peptide-types-categories-blends)
- [Lyophilised peptides: storage & handlingWhy research peptides arrive freeze-dried, and what keeps the powder stable.](https://www.australianresearchpeptides.au/articles/lyophilised-peptides-storage-handling)

Of the two forms compared here, Australian Research Peptides catalogues the no-DAC peptide only, paired with ipamorelin in one vial under Growth Hormone Research, orderable today with its batch certificate published, and dispatches it from Sydney across Australia.

## References

1. [Jette L, Leger R, Thibaudeau K, et al. Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog. Endocrinology 2005;146(7):3052-8 (PMID 15817669)](https://pubmed.ncbi.nlm.nih.gov/15817669/)
2. [Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab 2006;91(3):799-805 (PMID 16352683)](https://pubmed.ncbi.nlm.nih.gov/16352683/)
3. [Chapter MC, White CM, DeRidder A, Chadwick W, Martin B, Maudsley S. Chemical modification of class II G protein-coupled receptor ligands: frontiers in the development of peptide analogs as neuroendocrine pharmacological therapies. Pharmacol Ther 2010;125(1):39-54 (PMID 19686775, PMC2815023)](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2815023/)
4. [Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol 1998;139(5):552-61 (PMID 9849822)](https://pubmed.ncbi.nlm.nih.gov/9849822/)
5. [PubChem CID 56841945 — the record whose structure is the no-DAC peptide and whose synonym list also carries DAC names](https://pubchem.ncbi.nlm.nih.gov/compound/56841945)
6. [PubChem CID 91971820 — CJC-1295, the 30-residue DAC-bearing structure](https://pubchem.ncbi.nlm.nih.gov/compound/91971820)
7. [PubChem CID 16132413 — Sermorelin, GHRH (1-29), the unmodified comparison](https://pubchem.ncbi.nlm.nih.gov/compound/16132413)

## Related compounds

- [CJC-1295 (no DAC) + Ipamorelin](https://www.australianresearchpeptides.au/products/cjc-1295-ipamorelin)

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_All products supplied by Australian Research Peptides are for in vitro research purposes only._