Reconstitution
How to Reconstitute a Peptide
Reconstitution means turning a freeze-dried (lyophilized) peptide powder into a liquid you can measure and draw. The key idea: the amount of water you add decides your concentration, and therefore every dose.
What you're actually doing
A peptide vial contains a fixed amount of peptide as a dry powder, say 5 mg. Reconstitution adds a measured volume of liquid (bacteriostatic water) so the peptide dissolves evenly. The peptide amount never changes; you're only choosing how much liquid to spread it across, which sets the concentration in mg per mL.
What you need
- The peptide vial (note the mg printed on it)
- Bacteriostatic water (the diluent)
- A syringe to measure and transfer the water
- Alcohol swabs and a clean surface
Step by step
- Decide your water volume first. This sets your concentration, so choose it before you mix; see the chart below. A common choice is 1 to 3 mL.
- Clean both stoppers. Swab the bacteriostatic water vial and the peptide vial tops with alcohol and let them dry.
- Draw the water. Pull your chosen volume of bacteriostatic water into the syringe.
- Add it slowly. Insert the needle into the peptide vial and let the water run gently down the inside wall; don't blast it directly onto the powder.
- Dissolve gently. Swirl or let it sit until clear. Don't shake hard; peptides can be delicate.
- Calculate your dose. Now use the concentration to find the volume to draw for each dose.
How the water volume sets your concentration
For the same 5 mg vial, here's how different water volumes change the concentration and the volume you'd draw for a 250 mcg (0.25 mg) dose:
| Water added | Concentration | Draw for 250 mcg | Units (U-100) |
|---|---|---|---|
| 1 mL | 5 mg/mL | 0.05 mL | 5 |
| 2 mL | 2.5 mg/mL | 0.10 mL | 10 |
| 3 mL | 1.67 mg/mL | 0.15 mL | 15 |
More water = a more dilute solution = a larger, easier-to-measure draw per dose. Less water = more concentrated = a smaller draw. Neither changes how much peptide you actually take, only how much liquid carries it.
Find your concentration instantly
Enter the vial amount and water volume and the calculator shows your mg/mL plus the exact draw for any dose.
Open the free calculatorA note on storage
Once reconstituted, peptides are generally kept refrigerated and protected from light, and bacteriostatic water lets a vial be accessed multiple times. Follow the storage guidance for your specific product and your clinician's instructions; this guide covers the math, not medical handling.
This guide is for calculation and educational purposes only and is not medical advice. It does not recommend any peptide, dose, or protocol. Always consult a qualified clinician and follow sterile technique and product storage instructions.