Ipamorelin vs Sermorelin
Ipamorelin (Growth-hormone secretagogue (GHRP) / ghrelin receptor agonist) and Sermorelin (GHRH analog (growth-hormone-releasing hormone analog)) are documented as co-studied in the PeptiDex library. This page puts the two entries side by side on class, molecular weight, half-life, origin, mechanism and studied research areas — every value taken from the entry it belongs to.
Why these two are co-studied
Cross-referenced for research context — not a usage or combination recommendation.
At a glance
| Attribute | Ipamorelin | Sermorelin |
|---|---|---|
| Compound class | Growth-hormone secretagogue (GHRP) / ghrelin receptor agonist | GHRH analog (growth-hormone-releasing hormone analog) |
| Research category | Growth & GH-Axis | Growth & GH-Axis |
| Length (amino acids) | 5 amino acids | 29 amino acids |
| Molecular weight | 711.9 g/mol | 3357.9 g/mol |
| Half-life | ~2 hours (reported approximately 120 minutes) | Short, on the order of minutes (reported approximately 10-20 minutes) |
| Origin | Ipamorelin is a synthetic pentapeptide developed in the 1990s (originally by Novo Nordisk) as a selective growth-hormone secretagogue. It was designed to stimulate GH release with minimal off-target hormonal effects. | Sermorelin is a synthetic peptide corresponding to the first 29 amino acids of human growth-hormone-releasing hormone (GHRH 1-29), the shortest fully active fragment of GHRH. It was formerly marketed as Geref. |
“Not documented” means the PeptiDex entry records no value for that field. Nothing on this page is estimated, and no figure is carried over from one compound to the other.
How Ipamorelin works
Ipamorelin is an agonist of the growth-hormone secretagogue receptor (GHS-R1a, the ghrelin receptor), mimicking ghrelin to stimulate GH release from the anterior pituitary. It acts on the pituitary and hypothalamus to promote a pulsatile release of growth hormone. Unlike some other GHRPs, it is reported to be highly selective, releasing GH without significantly stimulating ACTH, cortisol, or prolactin at effective doses.
How Sermorelin works
Sermorelin is an agonist of the GHRH receptor on anterior-pituitary somatotrophs, stimulating the synthesis and pulsatile secretion of endogenous growth hormone. Because it acts upstream and preserves physiologic feedback, GH release remains subject to somatostatin regulation. Its effect on the GH/IGF-1 axis is thereby more physiologic than direct GH administration.
Mechanistic descriptions reflect published research-literature understanding and are quoted from each compound's own entry. Much peptide research is preclinical (in-vitro or animal-model); mechanism in humans may differ and is not established for many compounds.
Where each one appears in the literature
The research contexts each entry documents. Listing a research area is not a claim of efficacy or a therapeutic indication, and the two lists are not scored against each other.
Ipamorelin
Sermorelin
What sets each apart
Ipamorelin
Among GHRPs, ipamorelin is noted for its selectivity — stimulating GH release without the appetite, cortisol, and prolactin elevations associated with GHRP-6 and hexarelin.
Sermorelin
Sermorelin is a GHRH-receptor agonist (GHRH 1-29) rather than a ghrelin-receptor GHRP, and it is shorter-acting than modified GHRH analogs such as CJC-1295 or tesamorelin.
Frequently asked questions
Why is ipamorelin commonly studied alongside a GHRH analog like CJC-1295?
Ipamorelin (a GHS-R agonist) and a GHRH analog such as CJC-1295 or sermorelin act on two different receptor pathways. Research protocols pair them because combined GHRH + GHRP stimulation produces a synergistic, amplified GH pulse greater than either compound alone.
What is ipamorelin and what class of compound is it?
Ipamorelin is a synthetic pentapeptide growth hormone secretagogue (a ghrelin/GHS-R1a receptor agonist). It is studied as one of the most selective GHRPs, stimulating pulsatile GH release from the anterior pituitary with minimal effect on cortisol, prolactin, or ACTH in research models.
How does ipamorelin differ from GHRP-2 and GHRP-6?
All three activate the ghrelin receptor (GHS-R1a), but ipamorelin is the most selective: in the research literature it drives GH release without the appetite stimulation seen with GHRP-6 or the cortisol/prolactin elevation associated with GHRP-2. This selectivity is why it is frequently used as a reference GHRP in study design.
Why is sermorelin often studied with a GHRP?
Sermorelin acts on the GHRH receptor while GHRPs like ipamorelin or GHRP-2 act on the ghrelin receptor. Research pairing the two exploits the two complementary pathways to produce a larger, synergistic GH pulse than either alone.
What is sermorelin?
Sermorelin is a synthetic 29-amino-acid peptide corresponding to the biologically active amino-terminal fragment (residues 1-29) of human growth hormone-releasing hormone (GHRH). It binds the GHRH receptor on the anterior pituitary and is studied for its ability to stimulate the body's own GH production.
How does sermorelin differ from CJC-1295?
Both are GHRH analogs based on the GRF(1-29) sequence, but sermorelin is the unmodified fragment with a very short (~11-12 minute) half-life, whereas CJC-1295 adds amino-acid substitutions (and, in the DAC version, albumin binding) to resist enzymatic breakdown and extend duration substantially.
Answers are the ones published on each compound's own PeptiDex entry. They are educational summaries of research-literature context and are not medical advice.