21+ · VERIFIED LAB USE
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A step-by-step laboratory reference for reconstituting lyophilized research peptides: diluent choice, technique, concentration maths and storage of the prepared solution.
Research peptides ship as a lyophilized cake rather than a solution because peptides in water degrade. Freeze-drying removes the water under vacuum, leaving a porous solid that is stable for months at -20 C where the same material in solution would degrade in days.
The cake you see in the vial is the full stated mass of peptide. It looks like very little because most peptides are supplied in single- or double-digit milligram quantities, and a 10 mg cake occupies very little volume.
This is the step most often skipped and the one that causes the most avoidable loss. A vial taken straight from -20 C storage and opened immediately will condense atmospheric moisture directly onto the cake.
Leave the sealed vial on the bench for fifteen to twenty minutes before breaking the seal. For strongly hygroscopic material such as NAD+ this is not optional.
Sterile water and bacteriostatic water are the two standard choices. Bacteriostatic water contains 0.9% benzyl alcohol as a preservative, which is what allows a prepared solution to be held for longer without microbial growth.
Some sequences will not go fully into solution in neutral water. Hydrophobic peptides and those rich in aromatic residues often need a mildly acidic diluent - 0.6% acetic acid is the usual choice. Cagrilintide is the opposite case and dissolves faster in a mildly alkaline buffer.
Direct the diluent against the inside wall of the vial so it runs down onto the cake, rather than injecting it straight into the powder. This avoids splashing material up the vial walls where it will not redissolve.
Do not vortex or shake. Agitation shears longer sequences and whips air into the solution. Swirl gently or simply leave the vial standing; most cakes clear within a few minutes. Longer sequences such as TB-500 and Tesamorelin take longer and should be given the time.
Concentration in mg/mL is the vial mass divided by the diluent volume. A 10 mg vial reconstituted with 2 mL of diluent gives 5 mg/mL.
To find the volume for a given aliquot, divide the target mass by the concentration. A 250 mcg aliquot from a 5 mg/mL solution is 0.25 mg divided by 5 mg/mL, which is 0.05 mL. On a U-100 graduation that reads as 5 units.
The PeptideSeed reconstitution calculator does this arithmetic and also reports how many aliquots a vial yields at the chosen size.
Reconstituted peptide goes to 2-8 C, protected from light, and should not be frozen and thawed repeatedly. Each freeze-thaw cycle costs material.
Most sequences hold for around thirty days under those conditions. Disulfide-containing peptides such as Oxytocin and AOD-9604, and hydrolysis-prone material such as NAD+, have shorter windows - check the storage line on the individual product page.
This guide is general laboratory reference material relating to the handling of research compounds. It is not medical, veterinary or clinical guidance, and it does not describe or imply any use in humans or animals. All PeptideSeed material is supplied for in-vitro laboratory research only — see the terms of supply.