Peptide Calculator
This peptide calculator works out reconstitution: how far to fill a 0.3, 0.5 or 1 mL syringe for a target amount of peptide. Divide the vial's mg by the diluent mL for the concentration, then the target amount by that: 10 mg in 2 mL is 5 mg/mL, so 0.5 mg is 0.10 mL. For in-vitro laboratory research calculations.
Fill to 0.10 mL, 10 on a 100-mark scale. Concentration 5 mg/mL. Amounts per vial 20.
Fill to 0.10 mL
(10 on a 100-mark scale)
- Concentration
- 5 mg/mL
- Amounts per vial
- 20
Syringe volume (mL)
Peptide in the vial (mg)
Diluent added (mL)
Target amount (mg)
For in-vitro laboratory research calculations only. Not for human or veterinary use. Figures assume the mass on the vial label.
What is the peptide reconstitution formula?
The peptide reconstitution formula is two divisions: the vial's milligrams divided by the millilitres of diluent gives the concentration in mg/mL, and the target amount divided by that concentration gives the fill volume in mL.
Concentrationmg/mL = peptide in the vial (mg) ÷ diluent added (mL)
Fill volumemL = target amount (mg) ÷ concentration (mg/mL)
Scale readingmarks = fill volume (mL) × 100
Per vialamounts = vial (mg) ÷ target amount (mg), rounded down
Worked through with the figures the calculator opens on: 10 mg in 2 mL is 5.00 mg/mL, or 5,000 mcg/mL. 0.5 mg ÷ 5.00 mg/mL = 0.10 mL, which is 10 on a 100-mark scale, and the vial holds 20 amounts of 0.5 mg.
How much bacteriostatic water should I add to a peptide vial?
The amount of bacteriostatic water (BAC water) added to a peptide vial is a choice, not a fixed figure: it sets the concentration. Into a 10 mg vial, 1 mL gives 10 mg/mL and 2 mL gives 5 mg/mL.
Pick a volume that puts the fill volume well inside the syringe scale: between about 10 and 50 marks is easy to read. Less diluent gives a smaller fill volume; more gives a larger one.
What does “10 on a 100-mark scale” mean?
A 100-mark scale is a syringe barrel graduated with 100 marks per millilitre, so each mark is 0.01 mL and a fill volume of 0.10 mL sits on the 10th mark. The calculator gives both figures so the reading can be checked either way.
- A 0.3 mL syringe has 30 marks, labelled every 5.
- A 0.5 mL syringe has 50 marks, labelled every 10.
- A 1 mL syringe has 100 marks, labelled every 10.
- A reading with a decimal, such as 12.5, falls halfway between two marks.
Which syringe volume should I choose?
Choose the smallest syringe volume that holds the fill volume: a smaller syringe generally spaces its marks further apart, so a small reading is easier to see. If the fill volume is more than the selected syringe holds, the calculator says so; choose a larger syringe or add more diluent.
Peptide concentration table (mg/mL)
This peptide concentration table gives the mg/mL for 5, 10, 20 or 50 mg vials reconstituted in 0.5, 1, 2 or 3 mL of diluent. Multiply by 1,000 for mcg/mL.
| Vial | 0.5 mL | 1 mL | 2 mL | 3 mL |
|---|---|---|---|---|
| 5 mg | 10.00 | 5.00 | 2.50 | 1.67 |
| 10 mg | 20.00 | 10.00 | 5.00 | 3.33 |
| 20 mg | 40.00 | 20.00 | 10.00 | 6.67 |
| 50 mg | 100.00 | 50.00 | 25.00 | 16.67 |
Fill volume table for a 10 mg vial
This fill volume table gives the millilitres holding each target amount from a 10 mg peptide vial reconstituted in 1, 2 or 3 mL. Multiply by 100 for the mark on a 100-mark scale.
| Target | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 0.25 mg | 0.025 mL | 0.05 mL | 0.075 mL |
| 0.5 mg | 0.05 mL | 0.10 mL | 0.15 mL |
| 1 mg | 0.10 mL | 0.20 mL | 0.30 mL |
| 2 mg | 0.20 mL | 0.40 mL | 0.60 mL |
What is the difference between mg, mcg and mL?
Milligrams (mg) and micrograms (mcg, also written µg) measure the mass of peptide, and millilitres (mL) measure the volume of liquid. One milligram is 1,000 micrograms, so 1 mg/mL is the same concentration as 1,000 mcg/mL.
Does adding more diluent change the amount of peptide?
Adding more diluent does not change the amount of peptide in the vial; it lowers the concentration, so the same target amount needs a larger fill volume. A 10 mg vial holds 10 mg whether it is reconstituted in 1 mL (10 mg/mL) or in 4 mL (2.5 mg/mL).
That is also the fix when a reading falls below the first mark: more diluent gives a larger fill volume that is easier to read.
Handling notes for reconstitution
Reconstitution is the step where a freeze-dried peptide is dissolved in a measured volume of diluent, and a few habits keep the calculated concentration accurate.
- Measure the diluent volume carefully: the concentration is only as accurate as that figure.
- Run the liquid gently down the inside wall of the vial, then swirl to dissolve. Do not shake.
- Keep the reconstituted solution refrigerated at 2 to 8 °C and label it with its concentration and date.
Related guides
- Lyophilised peptides: storage and handling: how freeze-dried material is kept before and after it is mixed.
- BAC water vs sterile water: the two common diluents and how they differ.
- Certificates of Analysis: independent purity testing for each batch.