How to Reconstitute Hexarelin: Complete Laboratory Preparation Protocol Hexarelin (Examorelin, His-D-2-Methyl-Trp-Ala-Trp-D-Phe-Lys-NH2, MW 887.05 g/mol, CAS 140703-51-1) is a synthetic hexapeptide and the highest-potency synthetic GHSR-1a agonist among the growth hormone releasing peptides. It is supplied as a lyophilised white powder in a 10mL sterile glass vial containing 5mg of peptide. In addition to GHSR-1a activity, hexarelin is the only GHRP characterised as a CD36 receptor ligand, making it a unique dual-target research compound for GH axis and cardiovascular cell model studies. Materials Required Hexarelin 5mg lyophilised vial Bacteriostatic water (BAC water) — 10mL vial 1mL sterile syringe with needle Alcohol swabs (70% isopropyl) Nitrile gloves Permanent marker for labelling Refrigerator at 2–8°C for storage Pre-Reconstitution Preparation Inspect the hexarelin vial to confirm intact powder and an unbroken seal. Remove from cold storage and allow to equilibrate to room temperature for 10 minutes. Hexarelin contains a D-2-methyltryptophan residue that contributes to its high GHSR-1a potency — this modification has no impact on aqueous solubility and hexarelin dissolves readily in BAC water. Step-by-Step Reconstitution Protocol Step 1 — Prepare workspace. Clean work surface with 70% isopropyl alcohol. Allow to dry fully. Wear nitrile gloves. Step 2 — Swab both stoppers. Clean rubber stoppers on both vials with separate fresh alcohol swabs. Air dry 10 seconds each. Step 3 — Draw 2mL of BAC water. Draw 2mL of bacteriostatic water into a sterile syringe. Step 4 — Inject slowly along the vial wall. Direct the BAC water slowly down the inner glass wall of the hexarelin vial over 10–15 seconds. Do not inject directly onto the lyophilised powder cake. Step 5 — Dissolve gently. Swirl the vial gently for 20–30 seconds. Hexarelin dissolves readily and the solution should be clear and colourless. Do not shake or vortex. Step 6 — Inspect and label. Confirm full clarity. Label with reconstitution date, concentration, and initials. Resulting Concentration Adding 2mL BAC water to a 5mg hexarelin vial yields a stock concentration of 2.5mg/mL (2500mcg/mL). For GHSR-1a binding assays and CD36 receptor pharmacology studies in pituitary and cardiomyocyte cell model preparations, working concentrations of 0.01nM–1µM are prepared by serial dilution into assay buffer or serum-free media. Concentration Reference Table BAC Water Volume AddedResulting Concentration 1mL5.0mg/mL (5000mcg/mL) 2mL2.5mg/mL (2500mcg/mL) 5mL1.0mg/mL (1000mcg/mL) Storage Conditions and Stability Store lyophilised hexarelin at −20°C prior to reconstitution, protected from light and moisture. Once reconstituted, store at 2–8°C. Reconstituted hexarelin in BAC water is stable for up to 28 days under refrigeration. Do not freeze reconstituted solution. Hexarelin is stable in standard aqueous buffers at physiological pH. Prepare single-use aliquots for −80°C long-term storage to avoid repeat freeze-thaw degradation of working stocks. Troubleshooting Common Reconstitution Issues Powder not dissolving: Although rare for small hexapeptides, if any powder adheres to the glass wall, gently tilt the vial and swirl to bring it into contact with the solvent. Do not heat the vial. If dissolution remains incomplete after 60 seconds of gentle swirling, the vial may have been compromised by moisture ingress — inspect for any signs of a previously broken seal. Cloudy solution: A properly reconstituted solution should be clear and colourless. Cloudiness can indicate microbial contamination (do not use), peptide aggregation from incorrect pH or temperature, or introduction of particulate matter. Discard the vial if cloudiness persists after gentle swirling. Foaming: If foam forms during injection, this typically indicates the solvent was injected too quickly or directly onto the powder. Allow foam to settle naturally — do not shake. Once settled, gently swirl until fully dissolved. Foaming is rarely an issue with small hexapeptides but can occur if injection speed is too fast. Loss of compound on vial walls: Ensure all reconstituted solution is recovered by gently swirling the vial so the solution contacts all inner wall surfaces. For maximum recovery, invert the vial and draw from the stopper end using a syringe after dissolution is complete. Research Application Notes Hexarelin's exceptional GHSR-1a potency — consistently ranking as the highest-affinity synthetic GHRP in competitive radioligand binding assays using [125I]-ghrelin — makes it the preferred reference compound for establishing maximum GHSR-1a activation benchmarks in pituitary somatotroph cell models. When performing comparative GHSR-1a pharmacology studies, hexarelin's Emax defines the ceiling against which partial agonist activity of other compounds is calibrated. Its unique CD36 receptor activity in cardiomyocyte and vascular cell models requires additional receptor controls when used in cardiovascular cell biology assays — include CD36-blocking antibody controls to distinguish GHSR-1a-mediated from CD36-mediated signalling contributions. Hexarelin 5mg vials are available from Pinnacle Peptides, verified at ≥99% purity by HPLC and mass spectrometry. All content is intended for in vitro laboratory research purposes only. Not for human or animal consumption. Not intended to diagnose, treat, cure, or prevent any condition.