How to Reconstitute Peptides with Bacteriostatic Water
For a 10 mg research peptide vial, 2 mL of bacteriostatic water gives a 5 mg/mL solution, so the volume that contains 1 mg is 0.2 mL, or 20 units on a U-100 insulin syringe. Every other figure on this page is the same division with different inputs.
Vistara Labs peptides are supplied as lyophilised research material for laboratory use.
Quick answers
- CJC-1295 + Ipamorelin 10 mg vial: 2 mL of bacteriostatic water gives 5 mg/mL (full worked page)
- BPC-157 10 mg vial: 2 mL of bacteriostatic water gives 5 mg/mL (full worked page, also covers TB-500 and the BPC-157 + TB-500 blend)
- Peptide reconstitution calculator, preloaded with 10 mg in 2 mL
- Bacteriostatic water, 10 mL vial
- What bacteriostatic water is and why it differs from sterile water
- Lab Results: certificates of analysis
What you need
- The lyophilised peptide vial, still sealed, brought to room temperature.
- A 10 mL vial of bacteriostatic water (0.9% benzyl alcohol).
- A sterile syringe and needle for transferring the water (a 3 mL syringe moves 1 to 3 mL in one fill).
- Alcohol swabs for both rubber stoppers.
- A label for the concentration and date.
The concentration rule
Concentration is mass divided by volume: milligrams of peptide in the vial divided by millilitres of water added. Adding water never changes how much peptide is in the vial, only how much sits in each millilitre. A 10 mg vial holds 10 mg whether it is dissolved in 1 mL or 5 mL.
| Vial | 1 mL | 2 mL | 3 mL | 5 mL |
|---|---|---|---|---|
| 5 mg | 5 mg/mL | 2.5 mg/mL | 1.67 mg/mL | 1 mg/mL |
| 10 mg | 10 mg/mL | 5 mg/mL | 3.33 mg/mL | 2 mg/mL |
| 20 mg | 20 mg/mL | 10 mg/mL | 6.67 mg/mL | 4 mg/mL |
| 30 mg | 30 mg/mL | 15 mg/mL | 10 mg/mL | 6 mg/mL |
Read the row for your vial and the column for the water you added. For a blend such as the 10 mg CJC-1295 + Ipamorelin (No DAC) vial, the 10 mg is the total of both peptides (5 mg of each), so 2 mL gives 5 mg/mL of combined peptide, or 2.5 mg/mL of each component.
How to choose a water volume
There is no chemically correct volume; any column above dissolves the powder. The choice is about two practical things: how easy the solution is to measure, and how much solution there is to store.
More water means a lower concentration, so a given mass occupies more unit marks on the syringe. From a 10 mg vial, the volume that contains 1 mg is 10 units at 1 mL of water and 20 units at 2 mL. Twenty units is easier to read than ten, and a one-unit reading error is a smaller fraction of the total.
Less water means a higher concentration and a smaller total volume, so there is less solution to store. The trade-off is between measurement precision and total solution volume; the total peptide is identical either way.
For a 10 mg vial, 2 mL is the calculator default and the volume used in the examples on this page. Check that the vial has headspace for whatever volume you choose.
The numbers on this page are arithmetic about concentration and syringe graduations, not guidance about what quantity to use for any purpose. They were chosen because they make the maths easy to follow.
Reading the result on a U-100 syringe
A U-100 insulin syringe is graduated in units, where 1 mL = 100 units, so units = mL x 100. A 0.5 mL syringe holds 50 units and a 0.3 mL syringe 30 units; a unit is the same 0.01 mL on each, the smaller barrels just spread the marks out.
The volume that contains a given mass is mg divided by mg/mL; units are that volume times 100. The table uses a 10 mg vial in 2 mL (5 mg/mL) with arbitrary masses to show the pattern.
| Mass (illustrative) | Volume at 5 mg/mL | U-100 units |
|---|---|---|
| 0.25 mg | 0.05 mL | 5 units |
| 0.5 mg | 0.1 mL | 10 units |
| 1 mg | 0.2 mL | 20 units |
| 2 mg | 0.4 mL | 40 units |
Change the water and the units scale in step: at 3 mL (3.33 mg/mL) the volume containing 1 mg is 0.3 mL, or 30 units; at 1 mL (10 mg/mL) it is 0.1 mL, or 10 units. The calculator draws the fill line on a syringe diagram.
Technique, step by step
- Take the peptide vial out of cold storage and leave it sealed until it reaches room temperature. Condensation on cold glass is water you did not measure.
- Swab the stoppers of both vials with alcohol and let them dry.
- Draw the chosen volume of bacteriostatic water into the transfer syringe, tap out any air and settle on the exact mark.
- Push the needle through the peptide vial stopper at a slight angle so the tip points at the glass wall, not straight down at the powder.
- Depress the plunger slowly so the water runs down the glass and pools under the cake. A hard jet onto the powder can foam it or throw it up the walls.
- Withdraw the needle and swirl or roll the vial gently. Do not shake. Most lyophilised peptides dissolve within a minute or two; some are best left to stand.
- Check that the solution is clear and free of particles. Cloudiness, gel or floating material is covered in why peptides gel or go cloudy.
- Label the vial with the concentration (for example “10 mg / 2 mL = 5 mg/mL”) and the date, then refrigerate.
Storage
Once reconstituted, keep the vial refrigerated at 2 to 8 °C and protected from light; the original carton in the fridge is enough. The benzyl alcohol in bacteriostatic water is what allows the stopper to be pierced more than once; plain sterile water has no preservative and is intended for single access. Unopened lyophilised vials belong in the cold and dark as well, where the powder is far more stable than any solution. Swab the bacteriostatic water stopper before every draw and note the date it was first pierced.
Common mistakes
- Shaking the vial. Agitation encourages peptide molecules to aggregate, and foam is hard to measure. Swirl or roll instead.
- Using sterile water for a multi-access vial. Without a preservative there is nothing to slow microbial growth between draws.
- Adding water to a cold vial. Let it warm first; cold glass sweats.
- Guessing the vial size. The concentration is only as accurate as the mass you start from. Read the label.
- Forgetting that water changes concentration, not quantity. 3 mL instead of 2 mL does not give you more peptide, only a weaker solution and a different unit count for the same mass.
- Not labelling. Two unlabelled clear solutions look identical. Write the concentration on the vial the moment the water goes in.
Work it out for a different vial or concentration
The peptide reconstitution calculator opens preloaded with a 10 mg vial in 2 mL and a 1 mL (100 unit) syringe. Change the vial to 5, 20, 30 or any custom number, change the water, pick a 0.3, 0.5 or 1 mL syringe, and it redraws the fill line and the mg/mL figure. It works for any lyophilised peptide in the Vistara Labs catalogue or elsewhere.
Products this page applies to directly: CJC-1295 + Ipamorelin 10 mg, BPC-157 10 mg, TB-500 10 mg and the BPC-157 + TB-500 blend, with bacteriostatic water 10 mL as the diluent.
Reconstitution guides by compound
Each guide states the concentration for that vial size, converts it to U-100 syringe units and opens the calculator pre-set: BPC-157, TB-500 and the blend, CJC-1295 + Ipamorelin, retatrutide 10 mg and 20 mg, tirzepatide, tesamorelin, sermorelin 5 mg and 10 mg, ipamorelin, GHK-Cu 50 mg and 100 mg, GLOW Blend 70 mg, KLOW Blend 80 mg, KPV, MOTS-c 10 mg and 40 mg, SS-31, NAD+ 500 mg, glutathione 600 mg and 1500 mg, semax, selank, PT-141, Melanotan II, DSIP 5 mg, epitalon, 5-Amino-1MQ 50 mg, oxytocin 2 mg and HCG 5000 IU.
More guides
Before ordering or opening a vial: how to store research peptides, how to read a certificate of analysis, how to choose a research peptide supplier in Canada and where to get bacteriostatic water in Canada.
