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Lab tool

Peptide Reconstitution Calculator

Enter your vial details and target dose — we’ll calculate the exact volume to draw, down to the unit on your syringe.

Your vial

Draw this much

20units
on a 0.3 mL U-100 syringe  ·  = 0.2 mL
0102030
syringe scale: 0–30 units
Concentration
5 mg/mL
Doses per vial
10 draws
For laboratory research use only. This calculator is an educational reference and not medical guidance.

Peptide reconstitution guide

Reconstitution — dissolving a lyophilized (freeze-dried) peptide into solution — is the first and most error-prone step of any study. Done right, it preserves concentration accuracy, stability, and biological activity.

Peptides ship as dry powder to protect them in transit. Before use, the powder is dissolved in an appropriate diluent to a known concentration. The calculator above handles the math so you can focus on technique.

How to use the calculator

Four inputs, one exact answer.

1

Enter the peptide mass (mg) printed on your vial.

2

Enter the volume of bacteriostatic water you'll add (mL).

3

Set your target dose per draw (mcg or mg).

4

Read the exact units to draw on a U-100 syringe — and how many doses each vial yields.

Choosing the right diluent

The diluent you pick directly affects stability and solubility.

Bacteriostatic water

Sterile water with 0.9% benzyl alcohol as a preservative. Ideal for multi-draw vials; avoid with peptides sensitive to benzyl alcohol.

Sterile / sodium chloride 0.9%

Isotonic saline that mimics physiological conditions. A good general-purpose diluent for single-use preparations.

Buffer solutions (PBS, HEPES)

Maintain a defined pH range. Choose based on the peptide's isoelectric point and the demands of your assay.

Acetic acid solution

Typically 0.1–10% acetic acid in water. Useful for peptides with poor solubility in neutral-pH water.

Best practices

Wear gloves throughout handling to prevent contamination and degradation.

Let the vial reach room temperature before opening to avoid condensation.

Add diluent slowly down the vial wall — never directly onto the powder — to prevent foaming.

Swirl gently, don't shake. Vigorous shaking foams and degrades the peptide.

Warm difficult peptides gently (30–40°C); avoid prolonged sonication.

Aliquot into single-use volumes to avoid repeated freeze–thaw cycles.

Label and date every vial with peptide name, concentration, diluent, and storage conditions.

Storing reconstituted peptides

Temperatures below are for reconstituted solutions — not sealed lyophilized vials, which store at −20°C long-term.

2–8°CShort term (1–7 days) — refrigerated
−20°CMedium term (1–4 weeks) — standard freezer
−80°CLong term (months+) — ultra-low freezer
Label every stored vial with peptide name, concentration, diluent, date reconstituted, and storage conditions.

Common mistakes

Miscalculating concentration, leading to inaccurate dosing.

Using a diluent that's wrong for the peptide.

Shaking vigorously and foaming the solution.

Ignoring temperature during reconstitution.

Repeated freeze–thaw cycles that degrade the peptide.

Using contaminated diluents or non-sterile technique.

Frequently asked questions

Check the product documentation first. Hydrophilic peptides dissolve well in water or saline; hydrophobic ones may need a small amount of acetic acid or DMSO before dilution into an aqueous buffer. Always factor in your downstream application.

Try gentle warming (30–40°C) and more dissolution time. If that fails, brief sonication (5–10 min) can help. For very hydrophobic peptides, dissolve in a small volume of acetic acid (10%) first, then dilute with your final buffer.

Use aseptic technique and filter through a 0.22 µm sterile filter. Bacteriostatic water — or a sterile preservative like benzyl alcohol (0.9%) — helps prevent microbial growth in multi-draw vials.

It depends on sequence, diluent, and storage: roughly 1–7 days at 4°C, 1–4 weeks at −20°C, and months to years at −80°C. Sequences with cysteine, methionine, or tryptophan tend to have shorter shelf lives.

Generally not recommended. Media contains components that can interact with the peptide or affect solubility. Reconstitute in a simpler solution first, then dilute into media just before use.

Check the Certificate of Analysis or product documentation for exact mass or percent purity. Without it, your concentration calculations will only be approximate.

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