Reconstitution is the process of adding bacteriostatic water to a lyophilized (freeze-dried) peptide to create an injectable solution. The amount of water you choose directly affects your concentration, which determines how many syringe units you need per dose.
Why the Water Volume Matters
You can add any reasonable amount of water to a peptide vial — there is no single "correct" amount. But your choice affects two things:
- Dose precision: More water means more units per dose, which makes small doses easier to measure accurately on a syringe
- Injection volume: More water means you inject more liquid per dose
The goal is finding the balance between accurate measurement and comfortable injection volume.
Recommended Water Volumes by Peptide
These are practical starting points based on common vial sizes and typical dose ranges:
BPC-157 (5mg vial, typical dose 250-500mcg)
Add 2mL bacteriostatic water. This gives you 2,500mcg/mL, so a 250mcg dose is 10 units — easy to measure on any insulin syringe.
TB-500 (5mg vial, typical dose 2-2.5mg)
Add 1-2mL bacteriostatic water. Since the dose is larger (2,000-2,500mcg), you do not need as much dilution. With 1mL of water, a 2.5mg dose is 50 units.
Semaglutide (5mg vial, typical dose 0.25-2.4mg)
Add 2-3mL bacteriostatic water. The wide dose range during titration means you want enough dilution to measure the small starting doses (250mcg) precisely.
Ipamorelin (5mg vial, typical dose 100-300mcg)
Add 2.5mL bacteriostatic water. This gives 2,000mcg/mL. A 200mcg dose equals 10 units — clean and easy to read.
HGH/Somatropin (varies by brand, IU-based dosing)
Follow the manufacturer instructions. Most brands specify an exact water volume. For generic HGH, 1mL per 10 IU is a common standard.
How to Reconstitute Properly
- Clean the vial tops with an alcohol swab — both the peptide vial and the bacteriostatic water vial
- Draw the water into a syringe slowly
- Inject the water into the peptide vial by aiming the stream against the glass wall, not directly onto the powder. Let it run down the side gently
- Do not shake. Swirl gently or let it sit for a few minutes. Most peptides dissolve within 1-5 minutes on their own
- The solution should be clear. If it is cloudy or has particles floating, something may be wrong with the peptide
Bacteriostatic Water vs. Sterile Water
Bacteriostatic water contains 0.9% benzyl alcohol, which prevents bacterial growth. This means you can store the reconstituted vial and draw from it over multiple days.
Sterile water has no preservative — once opened, it should be used in a single session. For multi-dose vials (which is almost every peptide use case), bacteriostatic water is the correct choice.
Storage After Reconstitution
Once reconstituted, store the vial in the refrigerator at 36-46 degrees F (2-8 degrees C). Most peptides remain stable for 3-4 weeks when properly stored with bacteriostatic water. Do not freeze a reconstituted peptide — it can destroy the molecular structure.
Use our reconstitution calculator to find the exact concentration for any vial size and water volume combination.