Receptor target
- CJC-1295 (No DAC)
- GHRH receptor (GHRH-R)
- Ipamorelin
- GHSR-1a (ghrelin receptor)
By the Peptide.Express Editorial Team
Compound comparison
Two receptors on one pituitary cell, which is why these are usually combined rather than chosen between. CJC-1295 (No DAC) is a 29-residue GHRH-receptor analog signalling through cAMP-PKA; ipamorelin is a five-residue GHSR-1a agonist signalling through calcium. Neither has completed a phase 3 trial. GHRH-arm designs use CJC-1295 (No DAC); ghrelin-arm designs use ipamorelin.
Quick Answer
These two are almost never a choice — they are a pair. CJC-1295 (No DAC), also called Modified GRF (1-29), is a 29-residue GHRH-receptor analog (CAS 863288-34-0, 3,367.9 Da) signalling through cAMP-PKA. Ipamorelin is a 5-residue GHSR-1a agonist (CAS 170851-70-4, 711.9 Da) signalling through calcium mobilisation. Two receptors, two second messengers, one pituitary cell. Neither has a completed human phase 3 trial.


Receptor target
Mechanism class
Signalling cascade
Peptide length
Structure
CAS number
Molecular formula
Molecular weight
Reported plasma half-life
Cortisol and prolactin release
Highest published human trial stage
Regulatory status
Purity (Peptide.Express)
CJC-1295 (No DAC) compared with Ipamorelin across mechanism, structure and research attributes. Research reference only.
The reason these two are sold in one vial is not marketing convenience. A somatotroph integrates two independent inputs before releasing growth hormone, and each compound supplies one of them. CJC-1295 (No DAC) occupies GHRH-R and drives cAMP up. Ipamorelin occupies GHSR-1a and mobilises intracellular calcium.
Because the second messengers differ, the two signals do not simply add — the combined response in published pituitary models exceeds what either input produces alone. That is the design argument for pairing them, and it is also why "which one should I use" is usually the wrong question.
Structurally they have almost nothing in common. CJC-1295 (No DAC) is the GRF(1-29) fragment with four substitutions, of which the position-2 change carries most of the weight: it removes the dipeptidyl peptidase IV cleavage site that clears native GHRH within minutes. Ipamorelin is a fifth of the mass and three of its five residues are not proteinogenic. Alpha-aminoisobutyric acid, D-2-naphthylalanine and D-phenylalanine give it protease resistance and, more usefully, the receptor discrimination that separates it from GHRP-2 and GHRP-6, both of which stimulate cortisol and prolactin alongside growth hormone.
Where the published record thins out, it thins out for both. Neither compound has completed a phase 3 trial. Ipamorelin reached phase 2 for a gastrointestinal indication and development stopped there; CJC-1295 (No DAC) has no sponsor programme and no published human phase trial at all.
The commonly quoted half-life figures for both — around thirty minutes for the GHRH analog, various numbers for ipamorelin — trace to secondary sources rather than primary pharmacokinetic papers. The synergy claim itself rests on preclinical work on GHRH-plus-GHRP combinations generally, not on a trial of this specific pairing.
One registry note that trips people up: the PubChem entry indexed under the bare name "CJC-1295" (CID 91971820, CAS 446262-90-4) reports 3,647.2 Da, which corresponds to the DAC-bearing form rather than the 3,367.9 Da No-DAC material supplied here. The mass on the Certificate of Analysis is what distinguishes them. Sourced against a ≥99% HPLC purity specification. Third-party Certificates of Analysis are published where on file. For in-vitro laboratory research and educational use only.
No, and they are not even the same class. CJC-1295 (No DAC) is a 29-residue GHRH-receptor analog, also called Modified GRF (1-29). Ipamorelin is a 5-residue GHSR-1a agonist — a GHRP, not a GHRH analog. Different receptors, different second messengers, a 4.7-fold difference in molecular weight.
Because a somatotroph responds to two separate inputs and each compound supplies one. CJC-1295 raises cAMP through GHRH-R; ipamorelin mobilises calcium through GHSR-1a. Combining unrelated second-messenger pathways produces a larger response in preclinical models than either alone. No trial has tested this specific pairing in humans.
The question does not have an evidence-based answer, because no head-to-head study exists and the two do different jobs. If a design needs the ghrelin arm, ipamorelin is the tool; if it needs the GHRH arm, CJC-1295 (No DAC) is. Neither has completed a phase 3 trial or holds an approval anywhere.
Honestly, this is not well established for either. The roughly 30-minute figure quoted for CJC-1295 (No DAC) has no primary pharmacokinetic paper behind it, and ipamorelin's human plasma half-life is likewise uncharacterised in peer-reviewed literature. The long-acting compound in this family is CJC-1295 With DAC, a different molecule with an albumin-binding group.
Ipamorelin, marginally, and only because it went through a discontinued clinical programme that generated phase 1 and phase 2 data. CJC-1295 (No DAC) has no published human phase trial. Both bodies of work are dominated by preclinical models, and neither supports outcome claims.
Check the mass on the Certificate of Analysis. CJC-1295 (No DAC) is 3,367.9 Da. The DAC-bearing form is heavier — the PubChem record indexed under the bare name "CJC-1295" reports 3,647.2 Da — because it carries a maleimidopropionyl group that binds serum albumin. That group is the entire reason the DAC version lasts for days.
Compiled by the Peptide.Express Editorial Team. Written and reviewed by Peptide.Express Editorial Team. Molecular identity on this page (name, CAS number, molecular formula and molecular weight) is resolved from a single internal entity record and checked against primary registries (PubChem, CAS Common Chemistry) rather than retyped per page. A field with no verified value is left out instead of estimated. Literature is cited to a DOI, PMID or PMCID permalink so every reference resolves to the specific record it names.