CJC-1295 (No DAC) Purity Testing: HPLC, Mass Spec & CoA Guide

For laboratory research use only; not for human consumption.

What CJC-1295 (No DAC) is, chemically

CJC-1295 without DAC, also written Mod GRF (1-29), is a 29-residue analog of the first 29 amino acids of growth hormone-releasing hormone (GHRH). Native GHRH(1-29) is the shortest fragment that keeps full receptor activity, and it is the same backbone found in sermorelin. The "no DAC" form carries four amino acid substitutions relative to that backbone (D-Ala at position 2, Gln at 8, Ala at 15 and Leu at 27). They were introduced to slow enzymatic cleavage and to limit chemical degradation, and each one shifts the molecular mass by a predictable amount that a mass spectrometer can resolve.

"DAC" stands for Drug Affinity Complex, a reactive linker that lets a peptide bind serum albumin. The no-DAC form lacks it, so the molecule stays a plain peptide of about 3.4 kDa. That matters for testing: nothing about the analyte is unusual, and standard reversed-phase HPLC with electrospray mass spectrometry covers both purity and identity. The compound's research background is summarised in the CJC-1295 (No DAC) research overview.

Reversed-phase HPLC: what it separates

Reversed-phase HPLC separates the target peptide from truncated sequences and other synthesis-related impurities that accumulate across a chain this long. The resulting figure is read as described in understanding HPLC purity.

At 29 residues, every coupling step in solid-phase synthesis is an opportunity for a deletion sequence, and single-residue deletions often elute very close to the full-length product. Deamidation at asparagine or glutamine residues during storage produces another class of near-neighbor peaks, which is why older material can show a shoulder on the main peak that fresh material does not. Oxidation is less of a concern for this molecule than for methionine-rich peptides, but the sequence is not immune to it, and a diode-array trace across the peak can show whether a shoulder is a separate species.

Reading the chromatogram

A purity percentage is a ratio of peak areas: the area under the main CJC-1295 (No DAC) peak divided by the total area of every integrated peak at the detection wavelength, usually 214–220 nm, where the peptide bond absorbs. The figure therefore depends on method conditions. A shallow gradient on a C18 column resolves closely related impurities that a steep, fast gradient would fold into the main peak, so two reports quoting the same percentage are only comparable when column, gradient and wavelength are stated. On the trace itself, look for a flat baseline, a symmetrical main peak without shoulders, and an integration table that lists minor peaks instead of omitting them.

Mass spectrometry: confirming identity

A chromatographic peak shows that one species dominates; it does not show which species. Because the no-DAC form and its stabilized sibling CJC-1295 (DAC) differ by a distinct chemical modification, mass spectrometry is essential to confirm which variant a lot actually is, not just that it is roughly the right size. The two techniques answer different questions, as laid out in HPLC vs. mass spectrometry.

The theoretical average mass is close to 3,368 Da, compared with about 3,358 Da for unmodified sermorelin and about 3,647 Da for the DAC variant. Those three values are far enough apart that a single spectrum settles which GHRH(1-29) analog is in the vial.

Charge states and what the spectrum looks like

Electrospray ionization spreads a 3.4 kDa peptide across several positive charge states, typically the 3+, 4+ and 5+ ions. A good report shows the raw multiply-charged envelope and the deconvoluted neutral mass, with observed and theoretical values side by side. A deconvoluted mass that agrees within the instrument's stated accuracy confirms the molecular formula; a second, lighter or heavier series points to a co-eluting variant such as a deamidated form (about 1 Da heavier) or a deletion product.

Why this matters for a shorter-acting research tool

No-DAC CJC-1295's research value is tied to its comparatively short, pulsatile signaling window, described in the DAC vs. no-DAC comparison. A degraded or misidentified lot could produce a signaling profile that looks nothing like the intended pulsatile pattern, and in a receptor-binding or cell-signaling assay that would be indistinguishable from a real biological result unless the material was verified first.

The same reasoning applies to blends. When the peptide is combined with ipamorelin, as in the CJC-1295 (No DAC) + Ipamorelin blend, each component should appear as its own peak with its own confirmed mass; see also CJC-1295 + ipamorelin purity testing.

What an HPLC percentage leaves out

HPLC purity describes the peptide fraction only. A lyophilized vial also contains counter-ions left from purification, commonly trifluoroacetate or acetate, plus residual moisture, and neither appears in a UV chromatogram. Net peptide content can therefore be lower than gross powder mass even in a high-purity lot. Labs preparing quantitative stock solutions should account for this, and can use the peptide calculator to work out concentrations (mg/mL) after reconstitution.

Documentation to expect

A lot-specific certificate of analysis with HPLC purity and mass-spec identity confirmation is the baseline; see how to read a CoA for the field-by-field walk-through. In practice, a complete record for a CJC-1295 (No DAC) lot includes:

• A lot or batch number matching the vial label
• The HPLC chromatogram with method conditions and integrated purity
• A mass spectrum showing observed versus theoretical mass
• The test date and the laboratory that performed the analysis

Independent verification adds a reference point beyond a supplier's own analysis; the idea is explained in third-party testing explained. Current batch documents are published on the certificate of analysis page. The CJC-1295 (No DAC) product page lists the supplied sizes (5 mg and 10 mg), a purity specification of ≥98% by HPLC, and a lyophilized supplied form.

Keeping a verified lot verified

A certificate describes a lot at the moment it was tested. Lyophilized CJC-1295 (No DAC) is kept cold, dry and protected from light; the product page specifies refrigeration at 2–8 °C and −20 °C for long-term storage. Reconstituted solutions degrade faster than dry powder. Repeated freeze-thaw cycles, moisture ingress and prolonged time at room temperature can all generate new impurity peaks, so labs running long studies often aliquot material and re-test retained samples when results drift. General guidance is in storing research peptides.

A short verification checklist

1. Match the lot number on the vial to the lot on the certificate.
2. Confirm the observed mass sits near 3,368 Da, not 3,358 or 3,647.
3. Check that method conditions (column, gradient, wavelength) are stated.
4. Confirm the test date is plausible relative to the manufacture date.
5. Record any retained-sample result if a later experiment behaves unexpectedly.

The DAC variant has its own testing considerations; see CJC-1295 DAC purity testing.

CJC-1295 (No DAC) Purity Testing FAQ

Is CJC-1295 (No DAC) the same compound as Mod GRF (1-29)?

The names are used for the same tetrasubstituted GHRH(1-29) analog. A mass near 3,368 Da on the certificate is consistent with that structure.

How is it distinguished from sermorelin analytically?

Sermorelin is the unsubstituted GHRH(1-29) amide, about 10 Da lighter. Modern mass spectrometers resolve that difference easily, and the two also separate chromatographically under a suitable gradient.

How is it distinguished from the DAC form?

By mass. The DAC variant carries an albumin-binding linker and sits near 3,647 Da, roughly 280 Da heavier than the no-DAC form.

Which impurities are most relevant for a 29-residue peptide?

Deletion and truncation sequences from incomplete couplings, plus deamidated forms that accumulate with age or moisture exposure. Both are visible by HPLC when the gradient is shallow enough.

Does a high HPLC percentage guarantee the right peptide?

No. HPLC reports relative purity of whatever dominates the sample. Only mass spectrometry shows that the dominant species has the expected mass.

Why can net peptide content be lower than the vial's labeled mass?

The powder includes counter-ions and residual water that are invisible to UV detection. Net content is measured separately, for example by amino acid analysis.

What sizes does V8 Peptides list?

The product page lists 5 mg and 10 mg lyophilized vials with a purity specification of at least 98% by HPLC.

How should concentrations be calculated after reconstitution?

Divide the peptide mass by the diluent volume: 5 mg in 2 mL gives 2.5 mg/mL. The calculator on this site returns the same result and can account for net peptide content.

For laboratory research use only; not for human consumption. This article is research education, not usage guidance.

References

1. CJC-1295 (No DAC) research overview
2. Understanding HPLC purity
3. HPLC vs. mass spectrometry
4. How to read a CoA
5. Certificate of analysis page
6. CJC-1295 (No DAC) product page

Research Use Only. Supplied strictly for laboratory research and development; not for human or veterinary use, consumption, or any clinical or diagnostic purpose.