Is CJC-1295 29 or 30 residues?

29. GRF(1-29) means residues 1 to 29, and the peptide terminates in an amide rather than a thirtieth residue. The 30-residue description is a common error.

What is the molecular weight?

3647.2 Da with DAC, 3367.9 Da without. The 279.3 Da difference is the DAC linker.

Why do sources disagree about which form is which?

PubChem itself lists contradictory synonyms on one record. Comparing molecular weight is more reliable than comparing names.

What Is CJC-1295? GRF(1-29) and Its Two Forms

The short answer

CJC-1295 is a synthetic growth-hormone-releasing hormone analogue based on the first 29 residues of human GHRH, carrying four substitutions that resist enzymatic cleavage. It exists in two forms: with a Drug Affinity Complex at 3647.2 Da, and without it at 3367.9 Da.

Key facts

Basis: GRF(1-29), residues 1–29 of human GHRH
Length: 29 residues, C-terminal amide
Substitutions: D-Ala2, Gln8, Ala15, Leu27
With DAC: 3647.2 Da, PubChem CID 91971820
Without DAC: 3367.9 Da, CID 56841945, CAS 863288-34-0
DAC adds: 279.3 Da
Developer: ConjuChem

What it is built from

Human growth-hormone-releasing hormone is 44 residues, and its biological activity resides in the first 29, the fragment known as GRF(1-29), also marketed as sermorelin. CJC-1295 takes that fragment and substitutes four residues to slow enzymatic degradation. Despite frequent description as a 30-residue peptide, it is 29 residues terminating in an amide; PubChem's systematic name enumerates exactly 29.

The four substitutions and what each does

D-alanine at position 2 is the important one: DPP-4 cleaves after position 2 in GHRH, and a D-amino acid there is not a substrate. Gln8, Ala15 and Leu27 address other degradation points. The substitutions also remove the methionine present in native GRF(1-29), which is why Mod GRF's formula (C152H252N44O42) contains no sulfur where sermorelin's (C149H246N44O42S) does.

Research material referenced

CJC-1295 + Ipamorelin 5+5mg, third-party HPLC tested

Buy CJC-1295 + Ipamorelin · £36.99

The two forms, and the masses that separate them

With DAC, the peptide carries a maleimidopropionic acid linker that binds covalently to cysteine-34 of serum albumin, giving a half-life measured in days. Without DAC (the form usually called Modified GRF (1-29)), it clears in roughly half an hour. They differ by 279.3 Da, which is the linker. Supplying the mass alongside the name is the most reliable way to distinguish them.

Why the naming is so confused

PubChem record CID 56841945 carries both 'CJC 1295 with DAC' and 'CJC-1295-no DAC acetate' among its synonyms. The authoritative chemical database is internally inconsistent on this compound, so secondary sources inherit the confusion rather than causing it. This is why mass rather than name is the field to check.

Where it came from

CJC-1295 was developed by ConjuChem, and the DAC technology was the focus of the programme: a general approach to extending peptide half-life by covalent albumin attachment, applied here to a GHRH analogue. Teichman and colleagues reported on prolonged GH and IGF-I stimulation in healthy adults in the Journal of Clinical Endocrinology and Metabolism in 2006.

Regulatory position

CJC-1295 holds no marketing authorisation from the MHRA, EMA or FDA. Growth-hormone secretagogues are prohibited in sport under the World Anti-Doping Agency list. It is supplied here for laboratory research only.

Frequently asked questions

Is CJC-1295 29 or 30 residues?: 29. GRF(1-29) means residues 1 to 29, and the peptide terminates in an amide rather than a thirtieth residue. The 30-residue description is a common error.
What is the molecular weight?: 3647.2 Da with DAC, 3367.9 Da without. The 279.3 Da difference is the DAC linker.
Why do sources disagree about which form is which?: PubChem itself lists contradictory synonyms on one record. Comparing molecular weight is more reliable than comparing names.

Extended research context

The CJC-1295 & Ipamorelin deep dive

Deep dive: why CJC-1295 and Ipamorelin are studied together

CJC-1295 is a modified GHRH (growth-hormone-releasing hormone) analogue; Ipamorelin is a selective growth-hormone secretagogue that binds the ghrelin receptor (GHS-R1a). In pituitary-cell research models the two act on independent pathways whose downstream effect converges on GH release. CJC-1295 amplifies the endogenous GHRH signal while Ipamorelin adds a separate ghrelin-pathway stimulus. That's why supplier catalogues frequently package them together as a research reference blend.

DAC vs no-DAC: which CJC-1295 is which

'CJC-1295 with DAC' contains a Drug Affinity Complex (a Lys-maleimide moiety) that binds serum albumin and extends half-life to several days. 'CJC-1295 no-DAC' (also called Modified GRF 1-29) lacks the linker and clears in minutes. These are pharmacologically different peptides. A CoA must specify which form is in the vial; mass differs (~3,367 Da with DAC vs ~3,367 minus linker for no-DAC).

Ipamorelin's selectivity profile

Unlike earlier GHS-R agonists (e.g. GHRP-6), Ipamorelin was engineered for minimal cross-activity at cortisol- and prolactin-releasing pathways in research models. That receptor selectivity is why it is the reference secretagogue for controlled pituitary-cell studies.

Research applications

▸Pituitary-cell GH-release assays (comparator vs GHRH and hexarelin)
▸Half-life comparison studies: DAC vs no-DAC CJC-1295 forms
▸Ghrelin-receptor binding assays for Ipamorelin analogue development
▸Analytical HPLC method development for lipidated GHRH analogues
▸Stability testing under refrigerated storage

Handling checklist

✓Store lyophilised at −20 °C long-term
✓Reconstitute in bacteriostatic water; both peptides dissolve readily
✓Aliquot immediately, refrigerate at 2–8 °C, use within 28 days
✓Confirm salt form and DAC/no-DAC status on CoA before starting a study
✓Do not use for human administration (research reference only)

Common research-handling mistakes

Learnt from thousands of researcher orders across our UK labs.

✗ Confusing DAC and no-DAC CJC-1295

Fix: Check the CoA. The two have very different pharmacokinetics.

✗ Assuming Ipamorelin acts on GHRH receptors

Fix: It binds the ghrelin receptor (GHS-R1a), a separate pathway from CJC-1295.

✗ Storing reconstituted solution at room temperature

Fix: Refrigerate 2–8 °C after reconstitution.

Continue researching

Peer-reviewed guides, comparators and matched reference materials.

Primary sources & clinical trials

Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab and point to the primary source, so every claim can be verified at origin.

UKP

Written and reviewed by

The UK Peptides Editorial Team · Research library, UK Peptides

The editorial team is responsible for supplier selection, batch release decisions and the content published in this research library. Every article here is sourced to primary literature and every product page to a signed third-party certificate. Corrections are made in place and the review date updated.

How we write and check this content Report a factual error in this article

More CJC-1295 & Ipamorelin articles

Popular across the research hub

One flagship guide from every other research category.

← Back to Forum

What Is CJC-1295? The Two Forms and Their Masses