What is peptide reconstitution?

Reconstitution is the process of mixing lyophilized (freeze-dried) peptide powder with bacteriostatic water to create a solution for injection. Peptides are stored as powder for stability and must be reconstituted before use.

How much bacteriostatic water should I add?

The most common reconstitution is 1–2ml of bacteriostatic water per vial. Adding 1ml to a 5mg vial creates a 5mg/ml (5000mcg/ml) concentration — each 0.1ml (10 IU on a 100-unit syringe) = 500mcg. Use the calculator above to get your exact draw volume.

What syringe do I use for peptide injections?

Use 1ml insulin syringes with 29–31 gauge needles for subcutaneous injections. These are marked in IU (international units) where 1ml = 100 IU. The calculator shows both ml and IU values.

How long does reconstituted peptide last?

Reconstituted peptides stored in the refrigerator (not frozen) typically last 30–60 days. Unreconstituted lyophilized powder can last years if kept cool and dry. Always check for cloudiness or particulates before injecting.

What is bacteriostatic water?

Bacteriostatic water (bac water) is sterile water for injection that contains 0.9% benzyl alcohol as a preservative. The preservative allows the reconstituted vial to be used multiple times over several weeks, unlike plain sterile water which should be single-use.

Can I use regular water to reconstitute peptides?

No — regular tap or bottled water is not sterile and will contaminate the peptide. You must use bacteriostatic water (preferred, allows multi-use) or sterile water for injection (single-use only, no preservative).

Peptide Reconstitution Calculator — Exact Dosing in Seconds (2026)

Quick Presets — Common Peptides

Vial Size (peptide amount)

mcg

Bacteriostatic Water Added

Your Target Dose

mcg

Syringe Size

Draw Volume

0.10

milliliters (ml)

IU on Syringe

units

Concentration

5000

mcg/ml

Doses per Vial

injections

Draw 0.10ml (10 IU on a 100-unit insulin syringe). Your vial contains 10 doses at this dose level.

Step-by-Step Guide

How to Reconstitute Peptides

Follow these steps every time you reconstitute a new vial. Sterile technique is critical for injectable peptides.

Gather your supplies

You need: your lyophilized peptide vial, bacteriostatic water (not regular water, not saline), insulin syringes (1ml / 100 IU, 29–31 gauge), and alcohol swabs.

Swab both vial tops

Wipe the rubber stopper on both the peptide vial and the bacteriostatic water vial with an alcohol swab. Wait 30 seconds — don't blow on it or touch it after cleaning.

Draw the bacteriostatic water

Insert your syringe into the bacteriostatic water vial. Draw up the exact volume you calculated above (commonly 1–2ml per peptide vial). Remove air bubbles by gently tapping and pressing the plunger.

Inject water into the peptide vial — slowly

Insert the syringe into the peptide vial at an angle and slowly inject the water down the glass side of the vial, not directly onto the freeze-dried powder. This prevents foaming and peptide degradation.

Swirl gently — never shake

Gently swirl the vial until the powder fully dissolves. The solution should become completely clear. Never shake — this creates bubbles and can break peptide bonds, degrading your peptide.

Draw your dose and store the vial

Use the calculator result to draw the exact volume for your dose. Refrigerate the remaining vial immediately. Reconstituted peptides stored in the refrigerator last 30–60 days. Always inspect for cloudiness before injecting.

Reference

Common Reconstitution Quick-Reference

Standard reconstitutions for the most popular peptides. All use 1ml bacteriostatic water per vial unless noted.

Peptide	Vial Size	Bac Water	Concentration	Common Dose	Draw Volume
BPC-157	5mg (5000mcg)	1ml	5000mcg/ml	500mcg	0.10ml (10 IU)
BPC-157 (low)	5mg (5000mcg)	1ml	5000mcg/ml	250mcg	0.05ml (5 IU)
TB-500 (load)	5mg (5000mcg)	2ml	2500mcg/ml	2000mcg	0.80ml (80 IU)
TB-500 (maint)	5mg (5000mcg)	2ml	2500mcg/ml	1000mcg	0.40ml (40 IU)
Ipamorelin	2mg (2000mcg)	1ml	2000mcg/ml	200mcg	0.10ml (10 IU)
Semaglutide	2mg (2000mcg)	2ml	1000mcg/ml	250mcg	0.25ml (25 IU)
Tirzepatide	5mg (5000mcg)	1ml	5000mcg/ml	2500mcg start	0.50ml (50 IU)
Epithalon	10mg (10000mcg)	2ml	5000mcg/ml	500mcg	0.10ml (10 IU)