CJC-1295 vs Sermorelin vs Ipamorelin: Growth Hormone Secretagogues Compared
The literature on growth-hormone secretagogues often conflates two distinct receptor systems. Separating sermorelin and CJC-1295 from ipamorelin by mechanism clarifies comparisons among the three most studied compounds.
Two receptors, two families
GHRH analogs, including sermorelin and CJC-1295, act on the GHRH receptor in the anterior pituitary. The hypothalamus uses the same receptor to trigger natural GH pulses. Ipamorelin, a ghrelin mimetic, acts on the entirely separate GHS-R1a receptor, amplifying pulses and suppressing somatostatin (the brake on GH release). Published models find the two mechanisms synergistic, providing the rationale for pairing one compound from each family.
The three compounds
| Sermorelin | CJC-1295 (no DAC) | Ipamorelin | |
|---|---|---|---|
| Class | GHRH analog — GRF(1-29) | Modified GRF(1-29), four substitutions | Ghrelin mimetic, pentapeptide |
| Receptor | GHRH-R | GHRH-R | GHS-R1a |
| Half-life (research literature) | ~10–20 minutes | ~30 minutes | ~2 hours |
| Selectivity notes | Mimics native GHRH closely | Substitutions resist DPP-4 cleavage, retaining the same pulse shape with longer action | Notably selective: published data show minimal cortisol, prolactin or appetite signal vs older mimetics like GHRP-6 |
| History | Formerly an approved pediatric diagnostic/therapeutic (Geref), later withdrawn commercially | Research compound only | Reached early clinical trials (postoperative ileus), discontinued |
Pulsatility in research design
GH physiology is pulsatile. Downstream signaling, including IGF-1 induction and receptor sensitivity, depends on preserving that rhythm. Researchers therefore treat the short half-lives of GHRH analogs as a feature of study design. The long-acting DAC version of CJC-1295 flattens pulses into continuous elevation, making it a deliberately different pharmacological question.
Pairing logic in research protocols
A GHRH analog initiates the pulse; a ghrelin mimetic amplifies it and lifts somatostatin suppression. Published rodent and human physiology work found greater GH release from the combination than from either compound alone at the same doses. That result underlies the standard pairing in secretagogue research. We offer sermorelin (10mg vials) and ipamorelin (10mg vials). Within this group, tesamorelin is the only GHRH analog with current FDA approval (HIV-associated lipodystrophy) and is the natural positive-control choice.
For research use only — not for human or veterinary use.