Sermorelin reconstitution guide
Preparing and storing a laboratory stock of lyophilised sermorelin, and the handling factors that most affect a 29-residue peptide.
Laboratory handling of a research reagent only. Not a preparation guide for administration to any person or animal.
Why sermorelin needs more care
At 29 residues, sermorelin is considerably larger than the other peptides in this catalogue, and it carries a C-terminal amide. Longer peptides have more sites vulnerable to hydrolysis and oxidation, and more scope for aggregation, so handling matters more here than for a short fragment.
Storage
| State | Temperature | Guidance |
|---|---|---|
| Lyophilised, long term | −20 °C | Sealed, desiccated, protected from light. |
| Lyophilised, short term | 2–8 °C | Acceptable for near-term use. |
| Reconstituted | 2–8 °C | Short-lived. Prepare only what is needed. |
| Reconstituted aliquots | −20 °C or below | Single-use. Freeze–thaw cycling should be avoided entirely. |
Solvent and concentration
Sterile or bacteriostatic water is the standard laboratory choice. For a 5 mg vial:
| Solvent added | Resulting concentration |
|---|---|
| 1 mL | 5 mg/mL |
| 2 mL | 2.5 mg/mL |
| 5 mL | 1 mg/mL |
Sermorelin’s molecular weight is 3357.88 g/mol — roughly 2.4 times that of BPC-157. A stock at the same mass concentration is therefore a much lower molar concentration. Our current batch reports 4.8% water and 9.1% acetate; subtract both from vial mass for accurate molar work.
Technique
- Equilibrate the vial to room temperature before opening.
- Disinfect the stopper and allow it to dry fully.
- Add solvent slowly down the inner wall, never directly onto the cake.
- Allow to dissolve without agitation. Longer peptides are more prone to shear-induced aggregation, so avoid vortexing.
- Inspect for clarity. Any haze or visible particulate suggests aggregation and the stock should not be used.
- Aliquot into single-use volumes in low-binding tubes and freeze immediately.
Adsorption losses
Peptides adsorb to plastic and glass surfaces, and the effect is proportionally larger at low concentrations and with longer peptides. For dilute working solutions, use low-binding labware and prepare dilutions immediately before use rather than storing them.
Frequently asked questions
Why avoid vortexing?
Mechanical shear and the foaming it creates at the air–liquid interface both promote aggregation and degradation. This matters more for a 29-residue peptide than for a short fragment.
What does haze in a reconstituted vial indicate?
Most commonly aggregation. A correctly reconstituted stock should be clear and free of visible particulate; a hazy solution should not be used for quantitative work.