Peptide Reconstitution and Storage: A Lab Reference

Lyophilised peptides require careful handling. Reconstitution introduces water, oxygen, and surface contact — each capable of degrading the peptide if managed poorly. This guide covers solvent selection, concentration calculations, and storage practice for in vitro research workflows.

Choosing a solvent

The standard reconstitution solvent for most research peptides is sterile water or sterile bacteriostatic water (the latter contains 0.9% benzyl alcohol as a preservative and is preferred when a peptide will be stored in solution for more than a few days). Some peptides with poor aqueous solubility require dilute acetic acid (typically 0.1%) or DMSO at low percentages. The COA or supplier documentation should specify the recommended solvent.

Reconstitution technique

• Allow lyophilised peptide vial to reach room temperature before opening, to prevent moisture condensation
• Add solvent slowly down the vial wall, not directly onto the lyophilisate
• Swirl gently — do not vortex aggressively — to avoid aggregation
• Allow several minutes for full dissolution before use

Concentration calculations

Concentration is volume-dependent. For a 5 mg peptide reconstituted in 5 mL solvent, the resulting concentration is 1 mg/mL. To reach 2 mg/mL from the same vial, use 2.5 mL solvent. The molar concentration depends on molecular weight; the COA documents both the peptide mass and the molecular weight.

Storage

Lyophilised (unreconstituted) peptides should be stored at 2–8 °C, protected from light and moisture, in the original sealed vial. Most are stable for 24 months under these conditions. Reconstituted peptides should be stored at 2–8 °C for short-term use (under 30 days) or at −20 °C for longer storage. Avoid repeated freeze-thaw cycles — aliquot before freezing.

Compound-specific notes

GLP-1 class (Semaglutide, Tirzepatide, Retatrutide)

These compounds are stable but sensitive to surface adsorption at low concentrations. Use low-binding tubes when working below 100 µg/mL.

BPC-157 and TB-500

Both are highly soluble in sterile water and stable across a broad pH range. Standard handling applies.

GHK-Cu

The copper coordination is pH-sensitive. Avoid acidic solvents that may strip the copper centre.

Compliance

This guide is written exclusively for in vitro laboratory research. We do not supply, and this guide does not provide, reconstitution protocols for human or animal administration. See our terms of service and Australian regulatory guide for the full RUO framework.