Two Pathways, One Goal
GHRH Receptor Agonist
CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH). It binds to the GHRH receptor on pituitary somatotroph cells, stimulating the synthesis and secretion of endogenous GH. The standard form (without DAC) has a half-life of approximately 30 minutes; the DAC-modified version extends this to 6–8 days by binding covalently to serum albumin.
Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-ArgGhrelin Receptor Agonist (GHRP)
Ipamorelin is a synthetic pentapeptide growth hormone releasing peptide (GHRP) that mimics ghrelin by binding to the GHS-R1a (ghrelin) receptor. This pathway is entirely independent of the GHRH receptor, allowing simultaneous activation of both pathways when combined with CJC-1295. Ipamorelin is notable for its high selectivity — it does not significantly elevate cortisol or prolactin at research doses.
Aib-His-D-2-Nal-D-Phe-Lys-NH₂Because CJC-1295 and Ipamorelin act on completely independent receptor systems, their co-administration produces a synergistic effect on GH pulse magnitude that exceeds either compound alone. The GHRH pathway (CJC-1295) amplifies the pituitary's capacity to produce GH, while the ghrelin pathway (Ipamorelin) triggers the release pulse. Preclinical studies have consistently shown this dual-pathway stimulation produces greater IGF-1 elevation than either compound in isolation, making this the most studied GH secretagogue combination in the peptide research literature.
Head-to-Head Comparison
| Attribute | CJC-1295 | Ipamorelin |
|---|---|---|
| Peptide Class | GHRH analogue | GHRP / ghrelin mimetic |
| Mechanism | Binds GHRH receptor on pituitary somatotrophs → stimulates GH synthesis and release | Binds ghrelin / GHS-R1a receptor → triggers GH pulse independently of GHRH pathway |
| Amino Acid Length | 29 aa (CJC-1295); 30 aa with DAC modification | 6 aa (hexapeptide) |
| Half-life (no DAC) | ~30 minutes (CJC-1295 without DAC) | ~2 hours |
| Half-life (with DAC) | ~6–8 days (CJC-1295 with DAC) | N/A — no DAC form |
| GH Pulse Pattern | Amplifies baseline GH secretion; with DAC creates sustained elevation | Triggers discrete, sharp GH pulses mimicking natural pulsatile release |
| Cortisol / Prolactin Effect | Minimal effect on cortisol or prolactin | Highly selective — does not significantly raise cortisol or prolactin (key advantage over GHRP-6/2) |
| Hunger Stimulation | None | Minimal (much less than GHRP-6) |
| IGF-1 Elevation | Moderate to significant depending on dose/frequency | Moderate; synergistic when combined with CJC-1295 |
| Research Synergy | Commonly co-administered with Ipamorelin for dual-pathway GH stimulation | Commonly co-administered with CJC-1295 for amplified, pulsatile GH release |
| Storage | Lyophilized: room temp; Reconstituted: 2–8°C, use within 28 days | Lyophilized: room temp; Reconstituted: 2–8°C, use within 28 days |
| Purity Standard | ≥99% HPLC verified | ≥99% HPLC verified |
The DAC Question: Half-Life and Pulse Pattern
One of the most consequential decisions in CJC-1295 research protocol design is whether to use the DAC (Drug Affinity Complex) or non-DAC form. The DAC modification adds a lysine residue that forms a covalent bond with serum albumin, dramatically extending the half-life from ~30 minutes to approximately 6–8 days. This changes the fundamental character of GH stimulation.
Half-life ~30 min. When co-administered with Ipamorelin, produces a sharp, discrete GH pulse that mimics the natural pulsatile pattern. Preferred in research protocols studying acute GH secretion dynamics. Requires more frequent administration to maintain elevated GH levels.
Half-life ~6–8 days. Creates a sustained, elevated GH baseline rather than discrete pulses. Some researchers combine DAC-CJC-1295 with Ipamorelin to maintain a continuous GHRH signal while still triggering pulsatile release via the ghrelin pathway. Requires less frequent administration.
Ipamorelin's Selectivity Advantage
Among the GHRP family — which includes GHRP-2, GHRP-6, Hexarelin, and Ipamorelin — selectivity for GH release without co-stimulation of cortisol and prolactin is a key differentiator. The table below summarizes the selectivity profile across the major GHRPs studied in the literature.
| GHRP | GH Release | Cortisol Effect | Prolactin Effect | Hunger |
|---|---|---|---|---|
| Ipamorelin | Moderate | Minimal ✓ | Minimal ✓ | Minimal ✓ |
| GHRP-2 | Strong | Moderate ↑ | Moderate ↑ | Mild |
| GHRP-6 | Strong | Significant ↑ | Significant ↑ | Strong ↑ |
| Hexarelin | Very Strong | Significant ↑ | Significant ↑ | Moderate |
Frequently Asked Questions
Why are CJC-1295 and Ipamorelin almost always studied together?
They act on two completely separate receptor pathways — CJC-1295 targets the GHRH receptor while Ipamorelin targets the ghrelin/GHS-R1a receptor. When both pathways are activated simultaneously, preclinical research shows a synergistic amplification of GH pulse magnitude that is significantly greater than either compound alone. This dual-pathway approach is the most studied GH secretagogue combination in the literature.
What is the difference between CJC-1295 with DAC and without DAC?
DAC (Drug Affinity Complex) is a lysine modification that allows CJC-1295 to bind covalently to serum albumin, extending its half-life from ~30 minutes to approximately 6–8 days. CJC-1295 without DAC (also called Mod GRF 1-29) produces a more acute GH pulse when timed with Ipamorelin, while the DAC version creates a sustained baseline elevation. Researchers studying pulsatile GH release typically use the non-DAC form.
Does Ipamorelin raise cortisol or prolactin?
This is one of Ipamorelin's most notable characteristics in the research literature. Unlike GHRP-6 and GHRP-2, which significantly elevate cortisol and prolactin alongside GH, Ipamorelin demonstrates high selectivity for GH release with minimal impact on cortisol or prolactin at standard research doses. This selectivity profile is a primary reason it has become the preferred GHRP in combination protocols.
How does Ipamorelin compare to GHRP-6?
Both are GHRPs that stimulate GH via the ghrelin receptor, but they differ significantly in selectivity. GHRP-6 produces stronger GH pulses but also substantially elevates cortisol and prolactin, and causes significant hunger stimulation. Ipamorelin produces more modest but highly selective GH pulses with minimal side-receptor activity. For research protocols prioritizing selectivity and clean GH stimulation, Ipamorelin is generally preferred.
What does IGF-1 have to do with CJC-1295 and Ipamorelin research?
GH released by both peptides travels to the liver and stimulates IGF-1 (Insulin-like Growth Factor 1) production. IGF-1 is the primary downstream mediator of many GH effects studied in preclinical research, including protein synthesis, cellular proliferation, and metabolic regulation. Researchers often measure serum IGF-1 as a proxy biomarker for cumulative GH secretion over time when studying these compounds.
Are CJC-1295 and Ipamorelin the same as sermorelin?
No. Sermorelin is a truncated 29-amino-acid GHRH analogue (the first 29 aa of native GHRH), while CJC-1295 is a modified version with four amino acid substitutions that increase stability. Ipamorelin is structurally unrelated — it is a synthetic hexapeptide GHRP. All three stimulate GH release but through different mechanisms and with different pharmacokinetic profiles.
Related Compound Profiles
Key Published Research
Peer-reviewed studies from verified investigators — linked directly to PubMed
The landmark CJC-1295 clinical trial was conducted by Sam L. Teichman and Lawrence A. Frohman, MD (University of Illinois Medical Center), published in the Journal of Clinical Endocrinology & Metabolism in 2006. Ipamorelin was first characterized by Raun et al. at Novo Nordisk in 1998.
Prolonged Stimulation of Growth Hormone and IGF-I Secretion by CJC-1295, a Long-Acting Analog of GH-Releasing Hormone, in Healthy Adults
Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA.
Activation of the GH/IGF-1 Axis by CJC-1295 Results in Serum Protein Profile Changes in Normal Adult Subjects
Sackmann-Sala L, Ding J, Frohman LA, Kopchick JJ.
Ipamorelin, the First Selective Growth Hormone Secretagogue
Raun K, Hansen BS, Johansen NL, et al.
Effects of an Oral Ghrelin Mimetic on Body Composition and Clinical Outcomes in Healthy Older Adults
Nass R, Pezzoli SS, Oliveri MC, et al.
All citations link to verified PubMed records. This site does not fabricate or assign authorship — only real published investigators are listed.
Source CJC-1295 & Ipamorelin at Purgo Labs
Third-party tested, ≥99% purity, COA with every batch.