CJC-1295 with DAC and modified GRF (1–29) are different molecules

BioLabs Research

By BioLabs Research · Last reviewed: October 10, 2026

The name "CJC-1295" is used for two different backbones. One carries a covalent "drug affinity complex" (DAC) handle. The other is a substituted GRF (1–29) amide without that handle, often sold as "CJC-1295 no DAC" or "modified GRF (1–29)". These are different formulae with different masses, and they should never share an identity record.

This storefront does not list either molecule as a catalog SKU. This page is an identity note for purchasing and receiving teams who see the names on other sellers' paperwork. For how these names relate to the other compound names that often appear next to them, see our CJC-1295 and ipamorelin identity hub.

Where the name comes from

The name entered the peer-reviewed literature in 2005, when Jetté and colleagues described a set of GRF (1–29) analogues designed to form bioconjugates with albumin and identified one construct as CJC-1295 (Jetté et al., 2005). The design idea was a reactive maleimide group on an added C-terminal lysine. That group can form a covalent bond with a free thiol on albumin.

That chemical handle is what "DAC" means on paperwork. It is a structural feature, not a size or a strength.

How the two records differ

We do not print a formula or CAS number for the no-DAC form here, because we could not match it to one public registry record. Any supplier that sells it should print the formula, the expected mass and the observed mass on the lot certificate.

Why mismatched paperwork is a real problem

Labs often hold both forms under one nickname. The most common documentation errors are:

• One CAS number used for both forms. A COA that prints the DAC registry number next to the no-DAC backbone does not document identity. Give it the same weight as a missing lot number.
• Nickname-only labels. "CJC" on a carton tells receiving almost nothing. The formula and the observed mass decide identity.
• Mass not reported. The two forms have different formulae and therefore different masses (see the table above), so intact mass spectrometry tells them apart. A COA without an observed mass cannot settle the question.
• Merged inventory records. When both forms are logged under one stock number, later lots inherit the wrong certificate. Keep a separate inventory record for each backbone, even when both come from the same source.

If a lab already holds unlabeled material from this class, mark identity "unresolved" until the formula and observed mass match one row of the table above.

Quality markers for long synthetic peptides

Both forms are around 30 residues long. Longer synthetic peptides give more room for synthesis by-products, including deletion sequences, truncations and incomplete deprotection (D'Hondt et al., 2014). For any peptide in this size range, a useful COA includes:

• an HPLC chromatogram with the method ID, column and detection wavelength;
• intact mass by mass spectrometry, compared with the expected mass for the exact backbone named;
• for the DAC form, evidence that the maleimide handle is intact, since an altered handle changes the mass;
• a counter-ion and water statement, so area percent is not mistaken for net peptide content.

Reading a certificate for either form

Start with the header. A certificate that only says "CJC-1295" has not yet told you which backbone it covers, so look for the formula or the expected mass before anything else. Then compare the observed mass with the expected one. A match within the lab's stated tolerance settles the backbone; a mismatch outside that tolerance means the certificate and the vial describe different molecules. Only after identity is settled does the purity figure mean anything. Our guide on how to read lot documents covers each field, and the COA library shows complete certificates for catalog listings.

Handling and storage as laboratory material

General stability principles for peptides apply here (Manning et al., 2010). Store lyophilized material sealed, dry, cold and away from light, as the lot paper states, and keep exposure to warming and humidity to a minimum. The maleimide group in the DAC form is chemically reactive by design, so storage outside the stated conditions is a particular identity risk. Log every receipt against its lot certificate.

What this catalog actually lists

This catalog does not list CJC-1295 in either form, and we do not substitute another molecule for it. The current listings are in the catalog, and One vial, two CAS numbers shows how paperwork for a two-component vial should look. If your protocol names CJC-1295, contact the desk before you order. We will not guess an identity from a nickname.

Summary for receiving teams

• "CJC-1295" can mean two different backbones. Ask which one.
• The DAC form is PubChem CID 91971820, C165H269N47O46, ≈3647 g/mol.
• The no-DAC form needs its own formula, mass and CAS number on the lot COA.
• Identity comes from formula and observed mass, not from the name on the carton.
• Neither form is a catalog SKU on this storefront.

Related reading

• DAC vs no-DAC is a formula difference
• Lot docs are not a purity percentage

References

1. Jetté L, Léger R, Thibaudeau K, et al. Endocrinology. 2005;146(7):3052–3058. https://pubmed.ncbi.nlm.nih.gov/15817669/
2. PubChem Compound Summary, CID 91971820 ("CJC-1295"): formula C165H269N47O46, MW 3647.2. National Center for Biotechnology Information. https://pubchem.ncbi.nlm.nih.gov/compound/91971820
3. D'Hondt M, Bracke N, Taevernier L, et al. Related impurities in peptide medicines. J Pharm Biomed Anal. 2014;101:2–30. https://pubmed.ncbi.nlm.nih.gov/25044089/
4. Manning MC, Chou DK, Murphy BM, et al. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. https://pubmed.ncbi.nlm.nih.gov/20143256/

For research use only. Not for human or veterinary use.