Sermorelin Reconstitution Protocol: Step-by-Step Guide for Laboratory Research Sermorelin (GHRH(1-29)NH2, MW 3357.9 g/mol, CAS 86168-78-7) is a synthetic 29-amino acid N-terminal fragment of growth hormone-releasing hormone that retains full GHRH-R binding capacity. It is supplied as a lyophilised white powder in a 10mL sterile glass vial containing 5mg of peptide. As the reference GHRH-R agonist in pituitary somatotroph and GH axis cell model research, accurate reconstitution and proper handling are critical for generating reproducible receptor pharmacology data. Materials Required Sermorelin 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 sermorelin vial before use. The lyophilised powder should appear white to off-white, intact, and fluffy with a secure vial seal. Remove from cold storage and allow to equilibrate to room temperature for 15 minutes. This equilibration step is important for sermorelin — its 29-amino acid chain and moderate molecular weight mean it benefits from complete room temperature equilibration to ensure the solvent distributes evenly across the powder during dissolution, reducing the risk of localised under-dissolution. Step-by-Step Reconstitution Protocol Step 1 — Prepare workspace. Wipe the work surface with 70% isopropyl alcohol and allow to dry fully before starting. Wear nitrile gloves throughout to maintain aseptic conditions. Step 2 — Swab both vial stoppers. Clean the rubber stopper of the sermorelin vial and the BAC water vial with separate fresh alcohol swabs. Air dry for 10–15 seconds each. Step 3 — Draw 2mL of BAC water. Using a sterile syringe, draw 2mL of bacteriostatic water. The benzyl alcohol preservative in BAC water prevents microbial contamination during storage and is compatible with sermorelin's chemistry at standard working concentrations. Step 4 — Inject slowly along the vial wall. Insert the needle at an angle into the sermorelin vial with the needle tip directed against the inner glass wall. Slowly inject the BAC water in a controlled stream down the glass over 15–20 seconds. Directing the stream against the wall rather than the powder is particularly important for longer peptides like sermorelin to ensure gentle, even dissolution. Step 5 — Dissolve by gentle swirling. Gently swirl the vial in slow circular motions for 30–60 seconds. Sermorelin dissolves readily in aqueous media and should produce a clear, colourless solution within this time frame. Do not shake or vortex. If the powder requires additional time to dissolve, continue swirling gently — never apply mechanical force. Step 6 — Inspect for clarity. Confirm the solution is fully clear and free of particulate matter before storage or use. Sermorelin at 2.5mg/mL in BAC water produces a transparent, colourless solution. Step 7 — Label the vial. Record reconstitution date, concentration (2.5mg/mL), and researcher initials. Mark the 28-day expiry date on the label. Resulting Concentration Adding 2mL BAC water to a 5mg sermorelin vial yields a stock concentration of 2.5mg/mL (2500mcg/mL). For GHRH-R competition binding assays and cAMP accumulation studies in GH3 pituitary cell line preparations, working concentrations of 0.1nM to 100nM are standard, prepared by serial dilution into assay buffer or serum-free media immediately before use. 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 sermorelin at −20°C prior to reconstitution, protected from light and moisture. Once reconstituted, store at 2–8°C. Reconstituted sermorelin in BAC water is stable for up to 28 days under refrigeration. Do not freeze reconstituted solution. For long-term aliquot storage, prepare single-use aliquots and store at −80°C. Research Application Notes An important consideration specific to sermorelin in cell model research is its susceptibility to DPP-IV cleavage at the Ala8 position in serum-containing media. DPP-IV cleaves the N-terminal His-Ala dipeptide, generating the inactive fragment GHRH(3-29) which has substantially reduced GHRH-R binding affinity. For receptor pharmacology assays requiring prolonged compound exposure in serum-supplemented media, include a DPP-IV inhibitor (e.g. sitagliptin at 10µM, or diprotin A at 100µM) in the assay media to preserve sermorelin integrity throughout the incubation. Alternatively, use serum-free defined media conditions for assays where compound stability is critical. Sermorelin 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.