Ipamorelin vs Hexarelin: Research Comparison | Regena

Ipamorelin is a selective pentapeptide agonist at the growth-hormone-secretagogue receptor (GHS-R1a / ghrelin receptor), engineered for clean GH pharmacology without measurable effect on cortisol, prolactin or appetite in published research.

Hexarelin is a hexapeptide ghrelin-receptor agonist derived from GHRP-6 — potent at driving GH release but with measurable cortisol and prolactin effects at research doses, and additional cardiovascular-axis effects described in the published literature.

Both compounds act at the GHS-R1a receptor. Ipamorelin's selectivity is the key differentiator — it engages the growth-hormone axis without the cortisol / prolactin off-targets characteristic of first-generation GHRPs.

Hexarelin shows stronger GH-release potency at matched doses but the off-target cortisol and prolactin activity make it a less clean tool for isolating growth-hormone-axis signalling in research designs.

Ipamorelin has a short pharmacokinetic half-life (roughly two hours) and is typically used at once- or twice-daily research cadence.

Hexarelin has a similarly short native half-life and is used at once- to twice-daily cadence in research protocols; the higher potency per dose is offset by the wider off-target profile.

Ipamorelin is the standard GHRP arm in growth-hormone secretagogue research panels, particularly when paired with a GHRH analogue (CJC-1295 or tesamorelin) to combine both arms of the GH-release axis.

Hexarelin is used in cardiovascular-axis research where the additional off-target effects are part of the experimental design, and in comparator studies isolating the selectivity contribution of ipamorelin above the older-generation GHRP baseline.

Both Ipamorelin and Hexarelin ship from Regena only after independent third-party verification — Janoshik Analytical is the default verifier, with orthogonal independent laboratories used when batch chemistry calls for confirmation by a second method. Minimum release specification is ≥99.0% HPLC main-peak purity with matching mass-spectrometry molecular weight and water content within the published specification for the compound.

Batch COAs for both compounds are published on the Regena lab reports page so a research-peptide buyer can audit the analytical detail before purchase. The /trust/how-to-read-a-coa reference walks through every field on a modern Regena COA.

Both compounds ship lyophilised under nitrogen. Hold the unopened vial at 2–8 °C; freeze at −20 °C for long-term storage. Reconstitution with bacteriostatic water (0.9% benzyl alcohol) supports a 28-day in-use stability window under refrigeration for both compounds.

Aliquot before any freeze. The single most common cause of measurable potency loss in research peptides is repeat freeze-thaw cycling — both Ipamorelin and Hexarelin benefit from single-thaw aliquot workflows. Vortex gently, never shake aggressively, and keep reconstituted vials away from direct light. The /research/compound-storage-guide reference covers the per-compound stability windows in detail.

Researchers choose ipamorelin when the protocol requires clean ghrelin-axis GH release without cortisol / prolactin off-targets, or when pairing with a GHRH analogue for combined-axis growth-hormone research. Researchers choose hexarelin when the protocol targets the older-generation GHRP pharmacology directly, when the additional cardiovascular-axis effects are relevant, or when comparator studies isolate ipamorelin's selectivity advantage against a first-generation GHRP baseline.

For multi-compound comparator studies, the Regena consultations team will reserve matched-batch inventory of both Ipamorelin and Hexarelin against a project timeline so the experimental panel is sourced under a single analytical specification window.

Both Ipamorelin and Hexarelin are supplied strictly for in-vitro and preclinical research use. They are not medicines, are not approved for human consumption in Spain, the United Kingdom, the European Union or the United States, and are not dispensed against a prescription. The research-use declaration ships with every package alongside the independent third-party COA.

Comparison pages on the Regena site exist for laboratory-research reference. Nothing on this page constitutes a recommendation for human use of either compound.