Use this free peptide reconstitution calculator to work out the concentration of a reconstituted vial, how much to draw into a U-100 insulin syringe to reach a target amount, and how many draws a vial yields — instantly, as you type.
Reconstitution mathematics for laboratory research only. This tool performs volume/concentration calculations and is not medical, dosing, or administration advice. Peptides referenced are for research use only and are not for human consumption.
How to use the peptide reconstitution calculator
- Enter the peptide mass in the vial (in milligrams), shown on the vial or its certificate of analysis.
- Enter the volume of bacteriostatic water (in millilitres) you are adding to reconstitute it.
- Enter your target amount per draw and choose micrograms (mcg) or milligrams (mg).
- Read the results: the vial's concentration, the volume to draw shown in insulin-syringe units and millilitres, and the number of full draws per vial.
The peptide reconstitution formula
Reconstitution is simple ratio math. The concentration of a vial is the peptide mass divided by the volume of solvent added:
Concentration (mg/mL) = peptide (mg) ÷ bacteriostatic water (mL)
Because a U-100 insulin syringe holds 100 units per millilitre, one “unit” equals 1/100 mL. To find how many units correspond to a target amount, divide the target (in micrograms) by the concentration expressed in micrograms per unit:
Units to draw = target (mcg) ÷ [ concentration (mcg/mL) ÷ 100 ]
A worked example
Suppose a vial contains 10 mg of peptide and you add 2 mL of bacteriostatic water. The concentration is 10 ÷ 2 = 5 mg/mL, or 5,000 mcg/mL — which is 50 mcg per unit on a U-100 syringe. To reach a 250 mcg target you would draw 250 ÷ 50 = 5 units (0.05 mL), and the vial provides 10,000 ÷ 250 = 40 full draws. The calculator above does this instantly for any values.
Bacteriostatic water and insulin syringes
Reconstitution typically uses bacteriostatic water (sterile water containing 0.9% benzyl alcohol, which lets a reconstituted vial be stored longer) and a U-100 insulin syringe, where the barrel is marked in units rather than millilitres. Using more water makes each unit contain less peptide (finer resolution); using less water makes the solution more concentrated.
Reconstitution supplies
Reconstitution uses bacteriostatic water and a U-100 insulin syringe. Research-grade supplies are available from Frontier Peptide Labs — Bacteriostatic Water · Omnix Peptides — Bacteriostatic Water.
Sold for research use only — not for human consumption. Third-party affiliate/partner links; Vialology may earn a commission, which does not influence our editorial coverage.
Frequently asked questions
How do you reconstitute a peptide?
In research settings, a measured volume of bacteriostatic water is added slowly to the lyophilized (freeze-dried) peptide vial, letting it dissolve without agitation. The calculator handles the resulting concentration and volume math.
What does “mcg per unit” mean?
It is the amount of peptide contained in one unit (1/100 mL) on a U-100 insulin syringe, which makes measuring small volumes practical.
Does more bacteriostatic water change the total peptide?
No. The total peptide in the vial is fixed; adding more water only changes the concentration, so you draw a larger volume for the same target amount.
Is this a dosing calculator?
No. It performs reconstitution concentration and volume mathematics for laboratory research use. It is not medical or dosing advice.
Educational use only. This calculator and page provide reconstitution mathematics and general information for laboratory research contexts. They are not medical advice, dosing guidance, or instructions for human use. Peptides discussed are frequently experimental and are not approved by the FDA for human use. Always consult a licensed professional before making any health decision.