Lab tool
Reconstitution calculator
Enter the mass in the vial and how much diluent you plan to add. The calculator gives you the resulting concentration and what each mark on a standard insulin syringe delivers.
Bacteriostatic water for multi-draw vials; sterile water for single use.
Use a comma or a point for decimals.
Resulting concentration
5,000 mcg / mL
5 mg per mL
- Per syringe unit
- 50 mcg
- Full syringe delivers
- 5,000 mcg
- Vial contains
- 200 units total
Working backwards from a target
If you know the amount you want per syringe unit, this tells you how much diluent to add.
Add this much diluent
0.4 mL
Handling notes
What diluent should be used to reconstitute a lyophilized peptide?
Bacteriostatic water is the usual choice for multi-draw vials because the benzyl alcohol suppresses microbial growth between draws. Sterile water suits single-use preparations. Peptides that resist aqueous solution may need a small volume of dilute acetic acid or another co-solvent first, added before the bulk of the diluent.
How should diluent be added to the vial?
Direct the stream down the inside wall of the vial rather than onto the powder cake, and let the material dissolve without agitation. Swirl gently if needed. Vigorous shaking introduces shear and foaming that can denature peptide in solution.
How long does reconstituted peptide remain usable?
Once in solution, store at 2–8 °C protected from light and work within the planned study window rather than holding solution indefinitely. Solution stability is markedly shorter than that of the sealed lyophilized powder, which is stable for extended periods at −20 °C.
Supplies for this calculation
Background reading
Guides behind this calculation
Reconstitution Maths: Three Formulas Behind Every Peptide Calculator
Concentration, volume to draw, syringe units. Verify any calculator by hand in sixty seconds and see precisely where thousandfold slips…
Handling & storageReconstituting Lyophilized Peptides: A Lab Procedure With Worked Numbers
What makes a stock reliable comes down to three choices: the diluent, the volume, and how gently the cake goes into solution. The method…
ComparisonsBacteriostatic or Sterile Water: Choosing a Diluent for Peptide Reconstitution
A single preservative is the only thing that sets the two apart — and it determines whether a dissolved stock may be sampled again and…
Handling & storageTen Ways Peptide Vials Get Spoiled in the Lab — and the Fix for Each
Nothing here requires unusual chemistry. Every item has a cost you can put a number on, and every fix takes only moments.