CJC-1295 & Ipamorelin

Storage and Reconstitution for Both Compounds

UKPWritten & reviewed by The UK Peptides Editorial Team · Research library, UK Peptides2 min readLast reviewed 2026-08-233 cited sources

The short answer

Both are supplied lyophilised and most stable dry, cold and dark, and neither contains cysteine or methionine. The DAC form differs in one important way: its maleimide group is deliberately reactive toward thiols, which is a handling consideration the others do not have.

Key facts

Both supplied as
Lyophilised powder
Cysteine / methionine
Neither, in either compound
Ipamorelin MW
711.9 Da
CJC-1295 MW
3647.2 (DAC) / 3367.9 (non-DAC)
DAC-specific concern
Maleimide reacts with free thiols
Avoid with DAC form
Thiol-containing buffers

What the two share

Both lack cysteine and methionine, so disulfide chemistry and thioether oxidation do not apply to either. Both are supplied lyophilised, and both are most stable dry, cold and protected from light. Both should be reconstituted gently against the vial wall and swirled rather than shaken, since foaming indicates the air-liquid interface at which peptides denature.

The DAC form's specific reactivity

This is the one truly distinctive handling point in the category. The maleimide group exists to react with a free thiol; that is its entire purpose. It will react with any accessible thiol, not only albumin's Cys34. A buffer containing dithiothreitol, β-mercaptoethanol or free cysteine will consume the linker and destroy the conjugation chemistry before it reaches its intended target.

Research material referenced

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

Buy CJC-1295 + Ipamorelin · £36.99

Why that matters more than usual

For most peptides, a reducing agent in buffer is unnecessary but harmless. For the DAC form it is actively destructive, and the damage is invisible: the peptide remains intact and simply loses its ability to bind albumin. Nothing about the material would look wrong, and the half-life advantage would silently disappear.

Different masses, one common error

Ipamorelin at 711.9 Da and CJC-1295 at 3647.2 differ more than fivefold. Because the two are so routinely prepared together, using one molecular weight for the other is an easy and consequential slip. Labelling aliquots with the compound and its mass is a small discipline that prevents it.

After reconstitution

Aliquot into single-use volumes to avoid repeated freeze-thaw cycling, which concentrates solutes at the ice boundary and creates fresh interfaces each cycle. Ipamorelin's aromatic residues give it a useful 280 nm absorbance for concentration checking; CJC-1295 has aromatics too, from the tyrosines and phenylalanine in the GHRH sequence.

Frequently asked questions

Should I add a reducing agent?
No, and for the DAC form specifically it is destructive. The maleimide will react with the reducing agent's thiol instead of albumin's, silently removing the half-life advantage.
Do both compounds need the same handling?
Largely, but the DAC form's maleimide reactivity is unique to it. Neither contains cysteine or methionine.
What is the most common preparation error here?
Using one compound's molecular weight for the other. They differ more than fivefold and are usually prepared together.

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

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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

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Research use only. The information above is provided for scientific and educational reference. Compounds referenced are not approved for human use and are supplied for in vitro research or reference-material purposes only. No efficacy, safety, or therapeutic claims are made.

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