Almost all research peptides ship as lyophilized (freeze-dried) powder. Storing and reconstituting them correctly protects your samples and keeps experiments reproducible.
Why Peptides Are Lyophilized
Freeze-drying removes water under vacuum, which slows hydrolysis, oxidation, and microbial growth. In this form a peptide stays stable through shipping. In solution, the same peptide can degrade within days.
Storing Lyophilized Vials
- Short term: a cool, dark, dry place, or 2–8°C.
- Long term: -20°C or colder.
- Keep vials sealed and protected from light and moisture.
- Let a cold vial reach room temperature before opening so condensation does not form.
Choosing a Solvent
Bacteriostatic water (sterile water with 0.9% benzyl alcohol) is the most common laboratory diluent for multi-use vials. Sterile water suits single-use preparations. Some hydrophobic peptides need small amounts of acetic acid or DMSO, so always check the compound's solubility data.
General Reconstitution Steps
- Swab the vial stoppers with alcohol.
- Add the solvent slowly down the inside wall of the vial.
- Swirl gently until the powder dissolves. Do not shake or vortex.
- Label the vial with the concentration and date.
- Refrigerate at 2–8°C and avoid repeated freeze-thaw cycles.
Peptides Commonly Reconstituted in the Lab
BPC-157, TB-500, GHK-Cu, CJC-1295 + Ipamorelin, GLP-3 and NAD+. Shop all research peptides.
Calculating Stock Concentration
Stock concentration is the peptide mass in the vial divided by the volume of solvent you add. For example, 10 mg of lyophilized peptide in 2 mL of solvent gives a 5 mg/mL stock. Write the concentration on the vial label, and account for net peptide content if the COA reports it, because lyophilized peptides can contain counter-ions and residual moisture. Prepare working dilutions fresh in assay buffer.
Signs a Peptide Stock Has Degraded
- Cloudiness or particles in a solution that was previously clear
- Color change, except for copper complexes, which are naturally blue
- Loss of activity in a validated positive-control assay
If you suspect degradation, start a fresh vial from the same lot and compare.
What Lyophilization Actually Does
Lyophilization has three stages. The peptide solution is frozen, then ice is removed by sublimation under vacuum (primary drying), and finally bound water is removed at a slightly higher temperature (secondary drying). The result is a porous cake with very low residual moisture. That cake may look fluffy, compact or even nearly invisible in the vial, and none of these appearances indicates a problem. What matters is that the vial stays sealed and dry until you reconstitute it.
Dealing With Hard-to-Dissolve Peptides
Some peptides resist dissolving. Work out the net charge from the sequence first. Basic peptides often dissolve better in dilute acetic acid, while acidic peptides may need a mildly basic buffer. Very hydrophobic sequences may need a little DMSO before you dilute with aqueous solvent. Brief sonication in a water bath can help, but avoid heating.
Aliquoting Strategy
Instead of puncturing one vial over and over, many labs split a fresh stock into single-experiment aliquots in low-binding tubes and freeze them at -20°C or -80°C. Then each experiment starts from a stock that has been thawed only once.
Storage FAQ
Does a lyophilized vial need refrigeration during shipping? Most lyophilized peptides stay stable at ambient temperature for short transit periods. Move them to cold storage when they arrive.
When should sterile water be used instead of bacteriostatic water? Use sterile water for single-use preparations or for assays that are sensitive to benzyl alcohol.
Storage Checklist
- Lyophilized: cold, dry and dark
- Reconstituted: refrigerate, then aliquot and freeze
- Solvent: Bacteriostatic Water for multi-use vials
- Related: GH-axis peptide comparison and Reconstitution & Supplies
Research Use Only. All compounds referenced in this article are sold by Genetic Peptides USA strictly for in-vitro and laboratory research. They are not for human or animal consumption, are not drugs, foods, or cosmetics, and are not intended to diagnose, treat, cure, or prevent any disease. This article summarizes published scientific context for educational purposes and contains no dosing guidance.