Hexarelin vs Sermorelin
Hexarelin (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 | Hexarelin | 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) | 6 amino acids | 29 amino acids |
| Molecular weight | 887.0 g/mol | 3357.9 g/mol |
| Half-life | Short, on the order of tens of minutes (reported approximately 55 minutes) | Short, on the order of minutes (reported approximately 10-20 minutes) |
| Origin | Hexarelin (Examorelin) is a synthetic hexapeptide growth-hormone secretagogue, a structural analog of GHRP-6. It was developed as a potent GH-releasing peptide. | 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 Hexarelin works
Hexarelin is an agonist of the growth-hormone secretagogue receptor (GHS-R1a, ghrelin receptor), stimulating GH release from the pituitary. It is a potent GH secretagogue and also binds the CD36 scavenger receptor, which underlies research interest in cardiovascular effects. It can stimulate ACTH, cortisol, and prolactin release, and its GH response is known to attenuate (desensitize) with repeated exposure.
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.
Hexarelin
Sermorelin
What sets each apart
Hexarelin
Hexarelin is among the most potent GHRPs and uniquely binds CD36 (of cardiovascular interest), but it is less selective than ipamorelin and shows notable receptor desensitization.
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
What is hexarelin?
Hexarelin is a synthetic hexapeptide growth hormone-releasing peptide (GHRP) and ghrelin-receptor (GHS-R1a) agonist. It is noted in the research literature as one of the most potent GHRPs, driving GH release at lower doses than GHRP-6.
How does hexarelin differ from GHRP-6?
Hexarelin's sequence is nearly identical to GHRP-6 but carries a 2-methyl modification on the D-tryptophan residue. This substitution increases proteolytic resistance and potency, so hexarelin achieves comparable GH release at roughly 10-fold lower doses than GHRP-6 in research models.
Is hexarelin known for receptor desensitization?
Yes. The research literature notes that hexarelin, as a very potent GHS-R agonist, can lead to receptor desensitization with continuous high-dose exposure, which is a consideration in study design examining sustained versus intermittent stimulation.
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.
Why does sermorelin have such a short half-life?
The native GRF(1-29) sequence is rapidly cleaved in plasma by dipeptidyl peptidase-IV (DPP-IV) between residues Ala2 and Asp3. This gives sermorelin a plasma half-life of only about 11-12 minutes, so research protocols model brief, physiologic GH pulses.
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.