CJC-1295 is a long-acting GHRH analogue that acts at the GHRH receptor; ipamorelin is a selective ghrelin mimetic acting at GHSR-1a. The two compounds stimulate GH through distinct receptor systems that are synergistic when used together in research.
Research reference only — all information on this page summarises peer-reviewed scientific literature and does not constitute medical advice. View full compound profiles: CJC-1295 · Ipamorelin
Mechanism Comparison
CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH) that activates GHRH receptors in the pituitary somatotroph cells, increasing GH pulse amplitude. The DAC (Drug Affinity Complex) formulation extends half-life via albumin binding to ~8 days. Ipamorelin is a pentapeptide ghrelin mimetic acting at the GHSR-1a (ghrelin) receptor, stimulating GH release through a Gq-coupled pathway distinct from GHRH-R signalling. Because they activate different receptor systems — GHRH-R (Gs-coupled, cAMP) versus GHSR-1a (Gq-coupled, IP3/DAG) — their effects on GH secretion are mechanistically complementary and are commonly studied in combination protocols.
Side-by-Side Attributes
| Attribute | CJC-1295 | Ipamorelin |
|---|---|---|
| Receptor target | GHRH receptor (GHRH-R) | Ghrelin receptor (GHSR-1a) |
| Mechanism class | GHRH analogue | Ghrelin mimetic (GHRP) |
| Half-life | ~30 min (CJC-1295 no DAC) / ~8 days (with DAC linker) | ~2 hours |
| Effect on GH pulse | Increases GH pulse amplitude; prolongs somatotroph activation | Triggers GH pulse; selective — minimal cortisol/prolactin |
| Selectivity | GHRH-R selective | GHSR-1a selective; does not significantly elevate cortisol or prolactin |
| Cortisol/prolactin effect | Minimal (GHRH pathway) | Minimal (ipamorelin is the most selective GHS tested) |
| IGF-1 effect in rodent models | Sustained IGF-1 elevation (especially with DAC) | Pulsatile IGF-1 elevation |
| Regulatory status (US) | Investigational; 503A Cat 2 (restricted) | Investigational; 503A Cat 2 (restricted) |
| Route in published research | SC injection | SC injection |
Key Research Points
- 1CJC-1295 and ipamorelin are mechanistically complementary — they activate the two main receptor pathways that converge on pituitary GH secretion (GHRH-R and GHSR-1a), and published rodent research shows synergistic GH elevation when both are administered concurrently.
- 2Ipamorelin is considered the most receptor-selective GHRP studied: unlike GHRP-2 and GHRP-6, it does not significantly stimulate cortisol, prolactin, or ACTH at doses that produce robust GH release, making it a cleaner experimental tool for isolated GH axis research.
- 3CJC-1295 with DAC (albumin-binding linker) produces near-continuous GHRH-R stimulation over ~8 days, blunting the natural GH pulse pattern; CJC-1295 without DAC has a 30-minute half-life and is used when preservation of pulsatile GH patterns is important.
- 4Both compounds are classified 503A Category 2 by the FDA PCAC as of mid-2026, restricting them from domestic compounding pharmacy preparations.
- 5The GHRH-R and GHSR-1a pathways converge downstream at the level of pituitary somatotroph Ca²⁺ signalling — GHRH-R elevates cAMP/PKA while GHSR-1a elevates IP3/DAG — and co-stimulation produces greater GH secretion than either pathway alone in preclinical models.
Frequently Asked Questions
What is the difference between CJC-1295 and ipamorelin?
CJC-1295 is a synthetic GHRH (growth hormone-releasing hormone) analogue that activates GHRH receptors in pituitary somatotroph cells via a Gs/cAMP pathway, increasing GH pulse amplitude. Ipamorelin is a pentapeptide ghrelin mimetic that activates the GHSR-1a (ghrelin receptor) via a Gq/IP3 pathway, triggering GH release. The two compounds act at different receptor systems — making their GH-releasing effects complementary and synergistic — and ipamorelin is noted for its selectivity: it does not significantly elevate cortisol or prolactin at GH-releasing doses, unlike GHRP-2 or GHRP-6.
Why are CJC-1295 and ipamorelin often studied together?
CJC-1295 (GHRH-R agonist) and ipamorelin (GHSR-1a agonist) are studied together because they activate the two main receptor pathways that independently drive pituitary GH secretion. GHRH-R and GHSR-1a co-stimulation is synergistic — preclinical research demonstrates GH elevation substantially greater than additive when both pathways are simultaneously activated. The combination also mimics the physiological co-release of GHRH and ghrelin that normally triggers endogenous GH pulses.
What does CJC-1295 "with DAC" mean, and how does it differ from CJC-1295 without DAC?
CJC-1295 with DAC includes a Drug Affinity Complex linker — a maleimidopropionic acid moiety that conjugates to lysine-30 and forms a covalent disulfide bond with circulating albumin after administration, extending the half-life from ~30 minutes (no DAC) to approximately 8 days. The DAC version produces near-continuous GHRH-R stimulation and sustained IGF-1 elevation, blunting the natural pulsatile GH release pattern. CJC-1295 without DAC (also called Mod GRF 1-29) has a short half-life and is used when researchers want to preserve or study pulsatile GH secretion patterns.
Deep Dive
For extended mechanism analysis, trial data, and regulatory context, see the full research article:
CJC-1295 vs Sermorelin: GHRH Analogue Research Comparison →Full compound profile
CJC-1295
Full compound profile
Ipamorelin