How can I tell CJC-1295 with DAC from CJC-1295 without DAC?

By mass. The no-DAC peptide is C152H252N44O42 at 3367.9 g/mol average in PubChem, and the DAC version is C165H269N47O46 at 3647.2 g/mol. That gap of about 280 units is easy for mass spectrometry to see. Labels, vial caps and seller descriptions are not reliable, because the same name is used for both molecules.

What mass should a CJC-1295 COA show?

The mass of whichever version the vial claims to be, plus the measured value. For no DAC, 3367.9 g/mol average or about 3365.9 Da monoisotopic; for DAC, 3647.2 g/mol average or 3645.02 Da monoisotopic. A certificate that says "CJC-1295, identity confirmed" without naming the version or printing a measured mass has not confirmed identity for this compound.

Is Mod GRF 1-29 the same as CJC-1295?

Sellers use Mod GRF 1-29 for the no-DAC peptide: GRF(1-29) amide with D-Ala2, Gln8, Ala15 and Leu27. Doping-control papers call this peptide CJC-1295, while the developers' original CJC-1295 also carried a C-terminal maleimido lysine. So the two names overlap for one molecule and differ for the other. Testing by mass shows which one you have.

How do I know if my CJC-1295 is real?

Decide which version you paid for, then test a sample for identity by mass spectrometry, which shows DAC or no DAC directly. Add HPLC for purity, since a D/L swap at position 2 keeps the mass, and an amount test against the matching reference. A seller's certificate helps only if it names the version, the batch and the laboratory, and can be verified with the issuer.

One of the 30 compound testing profiles

CJC-1295

CJC-1295 is a name used for two molecules, the 29-amino-acid peptide without DAC (C152H252N44O42, average mass 3367.9 g/mol) and the 30-residue version with DAC (C165H269N47O46, average mass 3647.2 g/mol); a test should first show which one is in the vial, then measure it against the matching reference.

CJC-1295 was described by its developers as a tetrasubstituted analogue of human growth hormone-releasing factor (1-29) carrying a lysine with a maleimidopropionamide group at the C-terminus, designed to bond to serum albumin (Jetté et al., Endocrinology, 2005).

Test your CJC-1295

Identity card

Formula: Not a single molecule (see note)
Average mass: Not published
Monoisotopic mass: Not published
Length: Not applicable
Modifications: None listed
Also sold as: Mod GRF 1-29, CJC-1295 DAC, CJC no DAC
Note: The name covers two molecules, so no single identity is given. Without DAC (often sold as Mod GRF 1-29): Y-dA-DAIFTQSYRKVLAQLSARKLLQDILSR-NH2, 29 residues, hGRF(1-29) amide with D-Ala2, Gln8, Ala15 and Leu27; PubChem CID 56841945 gives C152H252N44O42, average mass 3367.9 g/mol, monoisotopic 3365.89 Da, and a doping-control paper lists the monoisotopic mass as 3365.9 Da. With DAC: the same peptide extended by a C-terminal lysine whose side chain carries a 3-maleimidopropionamide group; PubChem CID 91971820 gives C165H269N47O46, average mass 3647.2 g/mol, monoisotopic 3645.02 Da. PubChem's synonym lists for these records mix the with-DAC and no-DAC names, so match by formula, not by name.

Source: PubChem CID 56841945, CJC-1295 without DAC (C152H252N44O42), PubChem CID 91971820, CJC-1295 (with DAC), Knoop A et al. Qualitative identification of growth hormone-releasing hormones in human plasma by means of immunoaffinity purification and LC-HRMS/MS. Anal Bioanal Chem. 2016;408(12):3145-53, Jetté L et al. Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates: identification of CJC-1295 as a long-lasting GRF analog. Endocrinology. 2005;146(7):3052-8.

Compare the mass printed on a certificate with the values above. The mass checker explains charge states and which mass a lab usually reports.

What usually goes wrong with CJC-1295. Documented failure modes, with sources.

With DAC or without: the name does not say

The developers' CJC-1295 carried an added lysine at the C-terminus bearing a 3-maleimidopropionamide group (Jetté et al., 2005). Yet when the Norwegian doping-control laboratory analysed an unknown preparation submitted by police and customs, it found a 29-amino-acid peptide with a C-terminal amide, consistent with a peptide marketed as CJC-1295 (Henninge et al., Drug Testing and Analysis, 2010). Doping-control methods also use the name for the 29-residue peptide (Knoop et al., Analytical and Bioanalytical Chemistry, 2016). The two differ by about 280 mass units, so mass spectrometry tells them apart at once. Labels often do not.

A reactive group by design

The DAC version carries a maleimide, placed so that it bonds to the free thiol on Cys34 of serum albumin (Jetté et al., 2005). Any product of that group reacting with something else is a new molecule with a new mass. For the DAC version, a certificate should report not only that the main peak has the expected mass of 3647.2 g/mol (PubChem CID 91971820) but whether there are significant peaks at other masses, which LC-MS can name.

Asp3 and the residues the design replaced

Work on the parent hormone shows where GRF peptides break down: cleavage at Asp3-Ala4, isomerisation of Asp3 to beta-Asp3, and more rapid deamidation of Asn8 (Bongers et al., International Journal of Peptide and Protein Research, 1992). CJC-1295 keeps Asp3 but carries glutamine at position 8 and leucine at 27 (Knoop et al., 2016), removing the Asn8 deamidation route and the methionine that is most prone to oxidation (Butré et al., Molecules, 2023). An Asp3 cleavage product loses the first three residues and is easy to see by mass; a beta-Asp3 isomer has the same mass and needs chromatography.

D-alanine 2 and same-mass stereoisomers

Position 2 is D-alanine. A related pair shows how hard a single D/L difference can be to see: sermorelin and CJC-1293, which differ only by D-Ala2, could not be told apart in a published doping-control method because they share mass, retention time and product ion spectrum (Thomas et al., Analytical Science Advances, 2022). An L-Ala2 version of CJC-1295 would pose the same problem, and separating it needs a chromatographic method developed for it plus an authentic reference standard.

What we check in CJC-1295. Silent, with captions.

Which tests matter most

LC-MSAnswers the first question: about 3368 g/mol for the no-DAC peptide or about 3647 g/mol for the DAC version, or neither.
HRMSAccurate mass, near 3365.9 Da monoisotopic for no-DAC, confirms the four substitutions and flags adducts on the reactive DAC version.
HPLC-UVNeeded for same-mass variants such as a beta-Asp3 isomer or an L-Ala2 diastereomer that mass spectrometry cannot separate.
Peptide mappingConfirms Gln8, Ala15 and Leu27, the substitutions that distinguish CJC-1295 from sermorelin, and shows whether the C-terminal maleimido lysine is present and intact.
Counter-ion contentLets the amount be reported as peptide rather than salt, for whichever of the two molecules is present.

Reading CJC-1295 results

Labels commonly read 2 or 5 mg. The same label figure means a different number of molecules for each version, and an amount measured against the wrong reference will be off. A useful report names the molecule found by the identity test and the reference standard used for the amount, and the two should match. The US FDA has said CJC-1295 may have complexities with regard to peptide-related impurities and characterisation of the active ingredient (FDA, bulk substances with safety risks). The mass checker computes masses from a sequence for comparison.

Public Tested.ph results

No public CJC-1295 records yet

Each public CJC-1295 record will appear here with its identity, HPLC purity and measured amount against the label, once the first vial is tested.

FIG 13Amount against the label

Questions about testing CJC-1295

How can I tell CJC-1295 with DAC from CJC-1295 without DAC?: By mass. The no-DAC peptide is C152H252N44O42 at 3367.9 g/mol average in PubChem, and the DAC version is C165H269N47O46 at 3647.2 g/mol. That gap of about 280 units is easy for mass spectrometry to see. Labels, vial caps and seller descriptions are not reliable, because the same name is used for both molecules.
What mass should a CJC-1295 COA show?: The mass of whichever version the vial claims to be, plus the measured value. For no DAC, 3367.9 g/mol average or about 3365.9 Da monoisotopic; for DAC, 3647.2 g/mol average or 3645.02 Da monoisotopic. A certificate that says "CJC-1295, identity confirmed" without naming the version or printing a measured mass has not confirmed identity for this compound.
Is Mod GRF 1-29 the same as CJC-1295?: Sellers use Mod GRF 1-29 for the no-DAC peptide: GRF(1-29) amide with D-Ala2, Gln8, Ala15 and Leu27. Doping-control papers call this peptide CJC-1295, while the developers' original CJC-1295 also carried a C-terminal maleimido lysine. So the two names overlap for one molecule and differ for the other. Testing by mass shows which one you have.
How do I know if my CJC-1295 is real?: Decide which version you paid for, then test a sample for identity by mass spectrometry, which shows DAC or no DAC directly. Add HPLC for purity, since a D/L swap at position 2 keeps the mass, and an amount test against the matching reference. A seller's certificate helps only if it names the version, the batch and the laboratory, and can be verified with the issuer.

Sources

Jetté L et al. Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates: identification of CJC-1295 as a long-lasting GRF analog. Endocrinology. 2005;146(7):3052-8, PubMed
Henninge J et al. Identification of CJC-1295, a growth-hormone-releasing peptide, in an unknown pharmaceutical preparation. Drug Test Anal. 2010;2(11-12):647-50, PubMed
Knoop A et al. Qualitative identification of growth hormone-releasing hormones in human plasma by means of immunoaffinity purification and LC-HRMS/MS. Anal Bioanal Chem. 2016;408(12):3145-53, Analytical and Bioanalytical Chemistry (PMC)
Thomas A et al. Probing for peptidic drugs (2-10 kDa) in doping control blood samples. Anal Sci Adv. 2022;3(7-8):235-243, Analytical Science Advances (PMC)
Bongers J et al. Degradation of aspartic acid and asparagine residues in human growth hormone-releasing factor. Int J Pept Protein Res. 1992;39(4):364-74, PubMed
Butré CI et al. Interlaboratory Evaluation of a User-Friendly Benchtop Mass Spectrometer. Molecules. 2023;28(6):2855, Molecules (PMC)
Certain bulk drug substances for use in compounding that may present significant safety risks, US Food and Drug Administration
PubChem CID 91971820, CJC-1295 (with DAC), National Library of Medicine

Last reviewed 6 Oct 2026.