Guides
Reconstitution and storage
Peptides ship as a dry powder because powder is stable and solution is not. Two things decide how long a vial stays good: how the water goes in, and where the vial lives afterwards.
Water down the glass, not onto the powder
Run the diluent down the inside wall and let it reach the powder on its own, then swirl. Shaking foams the solution and shears the molecule. This one habit protects more purity than anything else you do at the bench.
Let the calculator do the division
Milligrams in the vial divided by millilitres of water is your concentration in mg/mL. The reconstitution calculator does that for every vial size we sell, and gives molarity too when the molecular weight is known. There is a preset page for each product.
Freezer for powder, fridge for solution
Dry powder keeps for months in a freezer and weeks in a fridge. Once reconstituted, refrigerate it and treat the clock as running. Repeated freeze-thaw cycles are how good vials go bad, so aliquot instead of refreezing.
Common questions
Which water should I use?
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Bacteriostatic water for anything you will draw from more than once. Its 0.9% benzyl alcohol slows microbial growth. Sterile water has no preservative and suits single-use preparation.
How much water goes in?
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Whatever volume gives a concentration that is easy to measure. 5 mg in 2 mL is 2.5 mg/mL; the same 5 mg in 1 mL is 5 mg/mL. The peptide amount never changes.
How long does a reconstituted vial last?
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Weeks in the fridge for most peptides, not months. Keep it cold and dark, and do not freeze it once it is in solution unless you have split it into single-use aliquots.
Can I freeze a reconstituted vial?
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Once, if you must, and only in aliquots. Freezing and thawing the same vial repeatedly degrades it.
Vial size in, water volume in, concentration out.
Open the calculatorGuides
- How to spot fake bacteriostatic waterA checklist for telling genuine bacteriostatic water from a fake or mislabeled vial, and when acetic acid is used instead to reconstitute a peptide.
- Where to buy bacteriostatic water for peptides in CanadaWhere to buy bacteriostatic water for research peptides in Canada, what the label should say, whether unopened vials expire, and why not to make your own.
- Is bacteriostatic water the same as reconstitution solution?Bacteriostatic water is one kind of reconstitution solution, not a synonym for it. How it compares, how long an opened vial lasts, and where to buy it.
- How to reconstitute 600mg and 1500mg glutathioneGlutathione vials hold 60 to 300 times the powder of a peptide vial. How much water to use, why the solution is acidic, and how to slow oxidation to GSSG.
- Bacteriostatic water vs sterile water for peptidesBacteriostatic water has a preservative that keeps a reconstituted peptide usable longer; sterile water does not. How they differ and when to use each.
- What is a peptide blend?A peptide blend is two or more research peptides lyophilized in one vial. What blends are, why peptides are combined, and how to verify a blended vial.
- What does "lyophilized" mean?Lyophilized means freeze-dried. Here's what that looks like in a peptide vial, why it's done, and what you do with the powder before use.
- How to reconstitute a lyophilized peptideThe right way to add water to a freeze-dried peptide vial, how to work out the concentration, and the handling mistakes that lower your purity.
- How to store research peptidesWhere to keep lyophilized and reconstituted peptides, how long they actually last, and the storage mistakes that quietly ruin a vial.