Written by PX1 Research Team
PX1 chemists and research educators with hands-on experience in US-based peptide manufacturing, HPLC / mass-spectrometry lot testing, and endotoxin QC. All content is citation-backed and peer-reviewed for accuracy.
Sermorelin vs CJC-1295 vs Ipamorelin: Complete Comparison
Research Guide
Reviewed By
PX1 QC — Analytical Chemistry Team
Every article is reviewed by PX1's in-house analytical team for accuracy on mechanism, dosing ranges reported in the literature, and lab-handling guidance. We do not publish clinical or medical advice.
Quick answer
GHRH analogs vs GHRPs, DAC vs no-DAC, and why sermorelin + CJC-1295 + ipamorelin get stacked together in research protocols.
Key takeaways
- Half-life: ~10–20 minutes
- Dosing pattern in research: typically pre-sleep to align with natural GH pulse
- Preserves natural pulsatility
- CJC-1295 no DAC (Mod-GRF 1-29): ~30-minute half-life. Preserves pulsatility.
The three most-compared GHRH peptides
Sermorelin, CJC-1295, and ipamorelin are the three peptides most frequently compared in growth hormone research. They are grouped together but two of them — sermorelin and CJC-1295 — are GHRH analogs, while ipamorelin is a GHRP (growth hormone releasing peptide), structurally and mechanistically distinct.
Sermorelin
Sermorelin is the first 29 amino acids of endogenous GHRH — the biologically active fragment. It binds the GHRH receptor on somatotroph cells of the anterior pituitary and stimulates pulsatile GH release.
- Half-life: ~10–20 minutes
- Dosing pattern in research: typically pre-sleep to align with natural GH pulse
- Preserves natural pulsatility
CJC-1295 (with and without DAC)
CJC-1295 is a modified GHRH analog engineered for longer half-life.
- CJC-1295 no DAC (Mod-GRF 1-29): ~30-minute half-life. Preserves pulsatility.
- CJC-1295 with DAC: Drug Affinity Complex binds serum albumin, extending half-life to 6–8 days. Produces sustained elevation in GH baseline — no pulsatility.
The DAC vs no-DAC distinction is the most consequential decision in this class. See CJC-1295 No DAC vs DAC (next research batch).
Ipamorelin
Ipamorelin is a pentapeptide GHRP — a growth hormone secretagogue receptor (GHSR) agonist, not a GHRH analog. Its distinguishing feature: high selectivity for GH release without significant cortisol, prolactin, or ACTH elevation.
- Half-life: ~2 hours
- Frequently studied stacked with a GHRH analog for synergistic GH release
Why they're stacked
GHRH analogs (sermorelin, CJC-1295) and GHRPs (ipamorelin, GHRP-2, GHRP-6) act at different receptors and produce synergistic — not merely additive — GH release when combined. The most commonly researched combination is CJC-1295 no DAC + ipamorelin.
Purity considerations
All three peptides are short enough that deletion-sequence impurities are the primary quality risk. Verify HPLC ≥99% and mass-spec identity per lot.
Research use only.
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