Lumera Labs Journal · Method note
CJC-1295 with vs without DAC: half-life implications for research
Published 2024-04-03 · Lumera Labs Editorial · Kelowna, BC
Short answer. CJC-1295 without DAC has an in-vivo half-life of about 30 minutes; with DAC (a maleimidopropionyl side chain that covalently binds serum albumin) the half-life extends to roughly eight days. Either form is supplied for in-vitro work; the choice depends on assay timescale.
What "DAC" means
DAC stands for drug affinity complex — specifically a maleimidopropionyl-lysine side chain at position 30 of the GHRH 1–29 backbone. The maleimide reacts in vivo with the free thiol on Cys34 of human serum albumin, forming a covalent adduct that protects the peptide from clearance and DPP-4 cleavage simultaneously.
Practical implications
- In-vitro receptor binding: the two forms perform identically in short-window assays (cAMP response within 30 minutes). DAC presence does not change GHRH-R affinity meaningfully.
- Pharmacokinetic models: use the DAC form for any study where extended exposure matters.
- Stability in storage: the maleimide group is air-sensitive; DAC lots have a slightly shorter functional shelf-life if not held under nitrogen.
- HPLC retention: DAC adds ~3 minutes to RP-HPLC retention time at standard gradients.
What to verify on the COA
For non-DAC CJC-1295, expect mass ~3367 Da. For DAC variant, mass ~3647 Da plus characteristic absorbance signature from the maleimide group at 220 nm. Net peptide ≥ 80%, endotoxin < 0.5 EU/mg, residual TFA < 1.0% are standard for both forms.
Stacking with Ipamorelin
CJC-1295 is commonly studied alongside Ipamorelin in growth-axis research models — the GHRH-analog plus selective ghrelin-receptor agonist combination is a classic synergy demonstration. CJC + Ipamorelin blend from $40 CAD in pre-blended ratios for direct receptor-co-engagement work.
Lumera Labs ships HPLC-verified CJC-1295 (no DAC) cold-chain across Canada from $25 CAD. View CJC-1295 (no DAC) on the catalog →
Frequently asked questions
Is CJC-1295 with DAC stronger?
Stronger isn't quite right — affinity at GHRH-R is similar. The DAC form persists longer in vivo, so cumulative exposure is higher at equivalent dose levels.
Which is more common in research?
Both are widely used. Short-timescale receptor work uses the non-DAC form; longer pharmacology models use DAC.
How is the DAC chemistry verified?
The maleimide signature shows at ~220 nm and the mass adds ~280 Da from the maleimidopropionyl group. A competent COA will show both.
Can the two forms be used interchangeably?
Only in short-window in-vitro assays. Time-course or in-vivo work should use whichever form was specified in the source publication.
Where to buy CJC-1295 in Canada?
Lumera Labs supplies both non-DAC and DAC forms HPLC-verified, shipped cold-chain from Kelowna.
Disclaimer: All Lumera Labs products are supplied for laboratory research use only. They are not approved by Health Canada for human consumption, therapy, or diagnosis. See our research-use declaration for full terms.