Hexarelin: What It Is Studied Alongside
Hexarelin is a synthetic growth hormone secretagogue peptide. This page summarises the research models and molecular pathways it has been studied alongside, including GHS-R1a signalling, MDM2/p53, CD36, and intestinal pe
Hexarelin is a synthetic hexapeptide belonging to the growth hormone secretagogue (GHS) class, also referred to in the literature as a growth hormone-releasing peptide. It is a GHS-R1a agonist, and it is this receptor — the growth hormone secretagogue receptor type 1a — that most of the experimental work on the compound centres on [6]. The peptide appears in the research literature alongside a defined set of study contexts: ischaemia/reperfusion acute kidney injury, retinal ganglion cell survival after optic nerve transection, MPTP-induced lung injury in mice, CD36 receptor modulation in a SARS-CoV-2 mouse model, and intestinal permeation-enhancer formulations studied by molecular dynamics simulation.
In the performance-enhancing peptide literature, hexarelin is grouped with other growth hormone secretagogues such as GHRP-2, GHRP-6 and ipamorelin, and distinguished from GHRH analogues such as sermorelin, tesamorelin and the CJC-1295 variants [2]. That review frames these agents as unregulated peptides marketed as research compounds and intended to modulate the GH-IGF-1 axis [2]. The sections below set out what each study actually measured, in which species or preparation, and where the evidence stops.
Research Studies
Hexarelin and MDM2/p53 signalling in ischaemia/reperfusion acute kidney injury
In a rat model of ischaemia/reperfusion-induced acute kidney injury, animals were pretreated with hexarelin at 100 μg/kg/d for 7 days and sacrificed 24 hours after the ischaemia/reperfusion insult. Kidney function, histology and apoptosis were assessed, and the work combined in vivo and in vitro experiments. The reported mechanism was alleviation of apoptosis via the MDM2/p53 pathway [1]. This is an animal and cell-culture finding; it does not establish an effect in humans.
Hexarelin and retinal ganglion cell survival after optic nerve transection
Hexarelin was studied for neuroprotective effect on retinal ganglion cell survival in the retina following optic nerve transection. The work used golden hamsters and describes hexarelin as a GHS-R1a agonist with a potent anti-apoptotic effect [6]. The endpoint was survival of retinal ganglion cells, not visual function in humans. This is an animal model of optic nerve injury.
Hexarelin and oxidative stress, IL-6 inflammation and caspase-3 apoptosis in MPTP-induced lung injury
A mouse study examined protective and therapeutic effects of hexarelin against MPTP-induced lung injury, evaluating oxidative stress, IL-6-mediated inflammation and caspase-3-dependent apoptosis. Fifty male Balb/C mice were used [5]. The findings are confined to a chemically induced lung injury model in mice.
Hexarelin and CD36 receptor modulation in a SARS-CoV-2 mouse model
Hexarelin appears in work on pharmacological targeting of the hyper-inflammatory response to SARS-CoV-2 infection in K18-hACE2 mice using a cluster of differentiation 36 (CD36) receptor modulator. That study addresses the hyper-inflammatory response progressing to acute respiratory distress syndrome as an unmet medical need, and notes that viral infection stimulates alveolar macrophages to adopt an inflammatory phenotype regulated at least in part through the pathway under investigation [3]. The model is a transgenic mouse; the relevance to human disease management is not established by this work.
Hexarelin and intestinal permeation enhancers in the presence of bile salts
All-atom molecular dynamics simulations were used to study the interaction between two permeability enhancers — sodium caprate and SNAC — and four peptides (octreotide, hexarelin, degarelix and insulin) in the presence of taurocholate, an intestinal bile salt. The enhancers had distinct effects on peptide release depending on their properties, promoting hydrophobic peptide release while inhibiting water-soluble peptide release. Lowering peptide concentrations in the simulations reduced peptide-peptide interactions but increased their interactions with something else in the system [4]. This is an in silico study of formulation behaviour, not a pharmacokinetic study in animals or humans.
Hexarelin and the GH-IGF-1 axis in the performance-enhancing peptide literature
Hexarelin is listed among the growth hormone secretagogues encountered in clinical practice and in online self-administration protocols, alongside GHRP-2, GHRP-6 and ipamorelin. The same review places GHRH analogues, the GH fragment AOD9604 (hGH 176-191) and IGF-1 analogues in the same broad category of agents intended to modulate the GH-IGF-1 axis [2]. That review is a survey of the landscape and of the gap between clinical evidence and self-administration; it is not a trial of hexarelin itself.
Hexarelin and GHS-R1a receptor pharmacology
The receptor family at the centre of hexarelin research is the growth hormone secretagogue receptor, specifically the type 1a subtype. Hexarelin is described in the retinal ganglion cell work as a GHS-R1a agonist [6], and the same receptor is the binding target described for other synthetic GHS peptides such as alexamorelin, which mimics ghrelin by binding GHS-R1a [7]. The GHS-R1a frame is what links the otherwise disparate tissue models above.
Hexarelin and comparison with other GHS and GHRH agents
The table below summarises how hexarelin is positioned relative to other agents in the same review, and what each entry is described as [2].
| Agent | Class as described | Context in the review |
|---|---|---|
| Hexarelin | Growth hormone secretagogue (GHS) | Listed among agents encountered in clinical practice and online self-administration protocols |
| GHRP-2 | Growth hormone secretagogue (GHS) | Same category as hexarelin |
| GHRP-6 | Growth hormone secretagogue (GHS) | Same category as hexarelin |
| Ipamorelin | Growth hormone secretagogue (GHS) | Same category as hexarelin |
| Sermorelin | GHRH analogue | Distinct class from the GHS entries |
| Tesamorelin | GHRH analogue | Distinct class from the GHS entries |
| CJC-1295 with DAC | GHRH analogue | Distinct class from the GHS entries |
| CJC-1295 without DAC | GHRH analogue | Distinct class from the GHS entries |
| AOD9604 (hGH 176-191) | GH fragment | Listed separately from GHS and GHRH entries |
| IGF-1 analogue | IGF-1 analogue | Listed separately from GHS and GHRH entries |
Hexarelin and study-model summary
The table below sets out the models in which hexarelin has been studied in the evidence above, the species or preparation used, and the reported endpoint. It is a map of the evidence, not a statement of effect in humans.
| Model or preparation | Species / system | Reported endpoint |
|---|---|---|
| Ischaemia/reperfusion acute kidney injury | Rat, plus in vitro experiments | Kidney function, histology, apoptosis; MDM2/p53 pathway [1] |
| Optic nerve transection | Golden hamster retina | Retinal ganglion cell survival [6] |
| MPTP-induced lung injury | Male Balb/C mice | Oxidative stress, IL-6 inflammation, caspase-3 apoptosis [5] |
| SARS-CoV-2 hyper-inflammation | K18-hACE2 mice | CD36 receptor modulation of inflammatory response [3] |
| Permeation enhancer interaction | All-atom molecular dynamics simulation | Peptide release in presence of taurocholate [4] |
If you are reading this for personal health reasons
Hexarelin as supplied here is sold for laboratory research use only, and we do not provide dosing or medical guidance. Nothing on this page is a recommendation for human use. Anyone considering a compound for themselves should speak to a licensed clinician.
Sources
- [1] Hexarelin alleviates apoptosis on ischemic acute kidney injury via MDM2/p53 pathway. https://europepmc.org/article/PMC/PMC10500723
- [2] The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. https://europepmc.org/article/PMC/PMC13322892
- [3] Pharmacological targeting of the hyper-inflammatory response to SARS-CoV-2-infected K18-hACE2 mice using a cluster of differentiation 36 receptor modulator. https://europepmc.org/article/PMC/PMC10879382
- [4] Revealing the interaction between peptide drugs and permeation enhancers in the presence of intestinal bile salts. https://pubmed.ncbi.nlm.nih.gov/37982184/
- [5] Protective and restorative effects of hexarelin on MPTP-induced lung injury in mice. https://pubmed.ncbi.nlm.nih.gov/42619489/
- [6] Hexarelin promotes the survival of retinal ganglion cells after optic nerve transection. https://europepmc.org/article/PMC/PMC13004568
- [7] Identification of alexamorelin consumption biomarkers using human hepatocyte incubations and high-resolution mass spectrometry. https://pubmed.ncbi.nlm.nih.gov/40465419/