Research Guide · GH Axis
CJC-1295 without DAC
CJC-1295 without DAC, also called Modified GRF (1-29) or "Mod GRF," is a short synthetic analog of growth hormone-releasing hormone. It is one of the most searched GH-axis research peptides, and it is usually confused with its long-acting cousin, CJC-1295 with DAC. This guide covers what separates the two and why researchers pair it with ipamorelin.
CJC-1295 (no DAC) and Ipamorelin are supplied in freeze-dried form. See all lyophilized peptide vials in the catalog.
← All research guidesWhat CJC-1295 without DAC is
Native growth hormone-releasing hormone (GHRH) is a 44-amino-acid peptide, but its full biological activity sits in the first 29 amino acids, a fragment known as GRF (1-29) or sermorelin. That native fragment breaks down in minutes in circulation.
Mod GRF (1-29) keeps the same 29-residue backbone and swaps four amino acids (positions 2, 8, 15 and 27) to resist enzymatic cleavage. The result is a GHRH analog that binds the same GHRH receptor but is far more stable than sermorelin in experimental systems, with a reported half-life of roughly 30 minutes.
With DAC vs without DAC
- Without DAC (Mod GRF 1-29): the modified 29-amino-acid peptide on its own. Short-acting, which preserves the pulse-like pattern of GH release that researchers studying the GH axis usually want to model.
- With DAC: the same peptide with a "Drug Affinity Complex," a reactive linker that binds the peptide to circulating albumin. That stretches its half-life to several days, and published human pharmacology work (Teichman et al., 2006) showed sustained elevation of GH and IGF-1 rather than discrete pulses.
- Why it matters for a study: pulsatile versus continuous GHRH-receptor signaling produce different downstream patterns, so the two are not interchangeable in an experiment. Always confirm which form a vial contains.
When a vendor lists only "CJC-1295," it is often unclear which form is meant. Ageless labels it explicitly: our vial is CJC-1295 (No DAC).
Why researchers pair it with ipamorelin
GH release from the pituitary is driven by two separate receptor pathways. GHRH analogs such as Mod GRF act on the GHRH receptor, while growth hormone secretagogues such as ipamorelin act on the ghrelin receptor (GHS-R1a). Studies of the GH axis have long reported that stimulating both pathways together produces a larger GH pulse than either alone.
Ipamorelin, a five-amino-acid secretagogue first described by Raun and colleagues in 1998, is studied in part because it was found to be highly selective for GH release, with little effect on ACTH or cortisol in the original animal work. That selectivity is why it is the most common partner for Mod GRF in GH-axis research.
What to look for in a research vial
- Clear labeling of No DAC vs DAC.
- Stated content per vial (ours: 10mg CJC-1295 No DAC + 10mg ipamorelin).
- Lyophilized (freeze-dried) powder, stored cold and protected from light.
- Third-party analytical testing you can review. See how to read a COA.
Quick facts
- Other names: Mod GRF (1-29), modified GRF 1-29, tetrasubstituted GRF (1-29)
- Length: 29 amino acids
- Target: GHRH receptor (pituitary)
- Common pairing: ipamorelin (GHS-R1a agonist)
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