Peptide Reconstitution and Storage: A Practical Reference

A vial taken straight from -20 °C is below the dew point. Opening it draws in moist air that condenses on the cold cake, and lyophilised peptide is hygroscopic — it will take up that water before you have added any diluent. For moisture-sensitive compounds, particularly maleimide-bearing analogues like CJC-1295 with DAC, this alone can compromise a lot.

Let a sealed vial equilibrate for fifteen to twenty minutes before breaking the seal. It costs nothing.

Bacteriostatic water contains 0.9 % benzyl alcohol and is appropriate where you want multi-use stability. Sterile water is the choice when the preservative would interfere with your assay, but it gives you a single-use solution.

Some compounds constrain the choice. Copper complexes require non-chelating diluent — citrate and EDTA buffers will strip copper from GHK-Cu and leave you with free tripeptide plus loose copper ions. Acidic sequences like Thymosin Alpha-1 dissolve better in water than in saline, because high ionic strength suppresses their solubility. Lipophilic compounds like Dihexa need a DMSO stock before any aqueous step. The product page for each compound states which applies.

Direct a slow stream of diluent against the inside wall of the vial so it runs down onto the cake rather than hitting it. Then swirl gently, or simply leave it to dissolve.

Shaking generates an air-water interface and shear, and peptides denature at interfaces. The visible sign is foam; the invisible sign is aggregated material that no longer counts toward your concentration. Long acylated peptides — semaglutide, tirzepatide, the whole incretin class — are the most sensitive to this. If you shake a vial and it foams, you have already lost material.

This is the single most valuable habit in peptide handling. Each freeze-thaw cycle costs a few percent through aggregation and adsorption, and those percentages compound. A stock frozen and thawed ten times has lost far more than a stock that was divided into ten single-use aliquots and frozen once.

Aliquot into low-binding tubes at the concentration you will actually use, freeze once, and thaw each aliquot exactly once. For cationic peptides like LL-37, low-binding labware is not optional — adsorptive loss to ordinary polypropylene is measurable at working concentrations and will look like degradation in your data.

It depends on the sequence, and honest answers vary. BPC-157 is genuinely stable — our stability data supports thirty days at 2–8 °C with under 2 % loss. Unmodified sermorelin is not, and we label it for seven days. NAD+ hydrolyses in aqueous solution within days regardless of temperature, and the hydrolysis product inhibits the enzyme most people are studying. Reduced glutathione oxidises on air contact and should be made fresh.

Treat any blanket '30 days for all peptides' claim as marketing. The reconstitution note on each Certus product page reflects that compound's own stability data, and where the honest answer is short we say so.

Tryptophan and tyrosine photo-oxidise; methionine oxidises readily with or without light. Hexarelin has two tryptophans, Semax has an N-terminal methionine, MOTS-c has two methionines, and copper complexes are photosensitive as complexes independent of their amino acid content. Amber vials or foil, and minimal bench time under lights, handle all of these.