Free laboratory tool
Peptide Reconstitution Calculator
Work out the concentration of a reconstituted lyophilized peptide in mcg/mL and mg/mL, the volume that holds a chosen aliquot amount, how that volume reads on a U-100 graduated barrel, and — with a molecular weight — the molar concentration.
Laboratory concentration arithmetic for in vitro research only. This tool does not provide dosing, administration or medical guidance.
What this calculator does — and does not do
Reconstitution turns a known mass of freeze-dried peptide into a solution of known concentration. Everything downstream — how much solution holds a given amount, and how that volume is measured — follows from two numbers you already have: the vial amount and the diluent volume.
It calculates
- Converts vial amount and diluent volume into concentration (mcg/mL and mg/mL).
- Finds the volume that contains a chosen aliquot amount, in mL and µL.
- Translates that volume into a U-100 graduation reading for 0.3, 0.5 or 1.0 mL barrels.
- Returns molar concentration (mM, µM) and nanomoles per aliquot when you enter a molecular weight.
- Estimates theoretical aliquots per vial and compares diluent volumes side by side.
It does not
- Choose a diluent volume or aliquot amount — those come from your SOP or method.
- Provide dosing, administration or any guidance for human or animal use.
- Account for syringe dead space, displacement volume or solution stability.
- Replace lot verification against the certificate of analysis.
How peptide concentration is calculated
Each result in the calculator comes from one of the formulas below. The worked numbers use the BPC-157 10 mg preset (10 mg vial, 2 mL diluent, 250 mcg aliquot); the molecular weight is the value stored in that preset. Compound chemistry and lot documentation are on the BPC-157 monograph.
1. Concentration
concentration (mcg/mL) = vial (mg) × 1000 ÷ diluent (mL)
10 mg in 2 mL of bacteriostatic water: 10,000 mcg ÷ 2 mL = 5,000 mcg/mL (5 mg/mL).
2. Volume per aliquot
volume (mL) = aliquot amount (mcg) ÷ concentration (mcg/mL)
250 mcg at 5,000 mcg/mL: 250 ÷ 5,000 = 0.05 mL, which is 50 µL.
3. U-100 graduation reading
graduations = volume (mL) × 100
0.05 mL reads as 5 graduations on a U-100 barrel, because 100 graduations fill 1 mL.
4. Molar concentration (optional)
concentration (mM) = mg/mL ÷ molecular weight (g/mol) × 1000
5 mg/mL at 1,419.55 g/mol ≈ 3.52 mM (3,522 µM); a 250 mcg aliquot is ≈ 176 nmol.
Concentration reference table (mcg/mL)
Resulting concentration for common vial strengths against the diluent volumes offered as presets. Use it to sanity-check a calculator result before it goes into a record.
| Vial | 1 mL | 2 mL | 3 mL | 5 mL |
|---|---|---|---|---|
| 2 mg | 2,000 | 1,000 | 667 | 400 |
| 5 mg | 5,000 | 2,500 | 1,667 | 1,000 |
| 10 mg | 10,000 | 5,000 | 3,333 | 2,000 |
| 15 mg | 15,000 | 7,500 | 5,000 | 3,000 |
| 20 mg | 20,000 | 10,000 | 6,667 | 4,000 |
| 30 mg | 30,000 | 15,000 | 10,000 | 6,000 |
Reading U-100 graduations
U-100 barrels are graduated in units rather than millilitres, and 100 units fill 1 mL. One graduation unit is therefore 0.01 mL, or 10 µL, whatever the barrel size — only the total capacity and the smallest printed mark change. The calculator warns when the volume you need exceeds the barrel selected.
| Barrel | Total units | Smallest mark |
|---|---|---|
| 0.3 mL | 30 | 0.005 mL |
| 0.5 mL | 50 | 0.01 mL |
| 1.0 mL | 100 | 0.01 mL |
Where reconstitution math goes wrong
- Reading milligrams as micrograms. A 10 mg vial holds 10,000 mcg, so a factor-of-1000 slip is the most common source of a wrong concentration.
- Treating U-100 graduations as microlitres. One graduation on a U-100 barrel is 0.01 mL, which is 10 µL — not 1 µL.
- Recording a concentration without the diluent volume that produced it. The number is meaningless in an audit trail unless the volume is recorded alongside it.
- Ignoring syringe dead space. The volume retained in the hub and needle is not delivered, which matters when aliquots are small relative to the barrel.
- Assuming the reconstituted volume equals the water added. Lyophilized powder displaces a small volume of its own, which is usually negligible but not zero at high vial strengths.
Reconstitution guide
For in vitro research use only. Not for human or animal consumption.
Lyophilized peptide reconstitution
VaultLabs peptides are supplied as lyophilized (freeze-dried) powders. Short-term transport fluctuations are normal, but integrity depends on proper storage. Before in vitro use, powder must be reconstituted with an appropriate solvent. Method notes: reconstitution basics and the UAE reconstitution guide.
Prepare the environment
Sterility and cleanliness matter for reproducible research handling. Wash hands, use sterile gloves and eye protection, and work on a clean bench. Typical items: lyophilized peptide vial, sterile syringe, bacteriostatic water, alcohol swabs, and labeled storage containers for aliquots.
Peptide and solvent preparation
VaultLabs recommends bacteriostatic water for most lyophilized research peptides. Allow cold-stored vials to reach room temperature before mixing. Disinfect rubber stoppers on both peptide and diluent vials before needle entry. Confirm the lot first in batch verification — how to read a peptide COA lists the fields to match.
Adding the solvent
Withdraw the planned BAC volume with a sterile syringe and dispense it slowly down the inside wall of the vial at ~45° to reduce foaming. Gentle swirling may help dissolution — avoid vigorous shaking unless your internal SOP specifies otherwise. The calculator above converts that volume into concentration; it does not choose the volume for you.
Storage of peptide solutions
Lyophilized powder: +4°C short-term; −20°C or lower for long-term archive. Reconstituted solutions have limited stability — many labs aliquot and freeze at −20°C, avoiding repeated freeze-thaw cycles that can degrade peptide integrity. Sealed-vial notes: research peptide storage guide.
Frequently asked questions
- What is a peptide reconstitution calculator?
- It is a laboratory arithmetic tool. You enter the amount of lyophilized peptide in a vial and the volume of diluent added, and it returns the resulting solution concentration, the volume that contains a chosen aliquot amount, and how that volume reads on a U-100 graduated barrel. With a molecular weight it also returns molar concentration.
- Is this calculator for medical dosing?
- No. The calculator only performs concentration and volume arithmetic for in vitro laboratory work. It does not provide dosing, administration, injection or treatment guidance, and VaultLabs materials are not for human or animal use.
- How much bacteriostatic water should I add to a 10 mg vial?
- The calculator does not choose a diluent volume — that comes from your laboratory SOP or method. What it shows is the consequence of each choice: 10 mg in 1, 2, 3 or 5 mL gives 10,000, 5,000, 3,333 or 2,000 mcg/mL respectively, as in the reference table on this page.
- Why calculate molar concentration as well as mcg/mL?
- Mass concentration does not account for molecular size, so two peptides at the same mcg/mL can differ several-fold in the number of molecules per millilitre. Entering the molecular weight converts mg/mL into mM and µM, and the amount per aliquot into nanomoles, which is how many in vitro assay concentrations are specified.
- How many aliquots does one vial give?
- Divide the total peptide in the vial by the amount per aliquot. A 10 mg vial is 10,000 mcg, so 250 mcg aliquots give a theoretical 40. Usable aliquots are always fewer once syringe dead space and the stability window of the reconstituted solution are accounted for.
- Should I verify the lot before I reconstitute a vial?
- Yes. Match the printed lot to the published certificate in batch verification, then file the PDF with your record. Reconstitution arithmetic does not replace incoming qualification of the material.
Materials and documentation
Diluent for reconstitution is listed as bacteriostatic water 10 mL, and lyophilized vials are in the research peptide catalog. Before calculating, check the lot in batch verification and read the certificate of analysis; after reconstitution, the peptide storage guide covers handling of solutions.
All VaultLabs products are supplied strictly for laboratory and research use only. They are not intended for human consumption, medical use, personal use, or diagnostic use.