Injection Technique

Peptide Reconstitution Guide

Most research peptides arrive as lyophilized (freeze-dried) powder that must be reconstituted with bacteriostatic water before use. Proper reconstitution technique preserves peptide integrity, ensures accurate dosing, and maximizes vial shelf life. This guide walks through every step from vial inspection to final storage.

Key Points

Lyophilized peptides must be reconstituted before use

Bacteriostatic water is the standard diluent (multi-use safe)

Run water down the vial wall—never spray directly on powder

Gentle swirl to mix—never shake

Reconstituted peptides last ~28 days refrigerated at 2-8°C

Label every vial with name, concentration, and date

Step-by-Step Guide

Inspect the Vial

Check that the peptide appears as a white to off-white powder or puck at the bottom of the vial. Discard if the powder appears discolored, wet, or if the seal is compromised.

Calculate Water Volume

Choose a water volume that makes dosing convenient. Example: 5mg vial + 2mL water = 2500mcg/mL (2.5mcg per unit on a U-100 syringe). More water = easier to measure small doses but larger injection volumes.

Prepare Bacteriostatic Water

Use bacteriostatic water (contains 0.9% benzyl alcohol preservative), NOT sterile water or saline. Bac water allows multi-use over 28 days. Wipe the bac water vial stopper with alcohol.

Draw the Water

Using a syringe (insulin or with drawing needle), draw the calculated amount of bacteriostatic water. Remove air bubbles by tapping and gently pushing plunger.

Add Water to Peptide Vial

Wipe the peptide vial stopper with alcohol. Insert needle and let the water run down the inside wall of the vial. Do NOT squirt directly onto the powder—this can damage the peptide.

Aim the needle toward the glass wall and let water trickle down gently.

Mix Gently

Swirl the vial gently in a circular motion. Do NOT shake, vortex, or invert aggressively. Peptides are fragile proteins that can denature with rough handling. Let it sit for a few minutes if powder remains.

Verify Solution Clarity

The reconstituted solution should be clear and colorless. Some slight foaming on top is normal and will dissipate. If cloudy or contains particles, do not use.

Label and Store

Label the vial with: peptide name, concentration (mcg/unit), reconstitution date, and expiry (28 days). Store in refrigerator at 2-8°C (36-46°F). Never freeze reconstituted peptides.

Warnings & Precautions

!Never shake a peptide vial—gentle swirling only.
!Use bacteriostatic water, not sterile water, for multi-use vials.
!Reconstituted peptides expire in ~28 days when refrigerated.
!Discard any solution that becomes cloudy, discolored, or contains visible particles.
!Do not freeze reconstituted peptides—this destroys the protein structure.

Frequently Asked Questions

Can I use sterile water instead of bacteriostatic water?

Sterile water lacks preservative and should only be used for single-use vials consumed immediately. Bacteriostatic water (with 0.9% benzyl alcohol) prevents bacterial growth, allowing safe multi-use for up to 28 days.

How do I calculate the concentration after reconstitution?

Divide the total peptide amount by the water volume. Example: 5mg peptide + 2mL water = 2.5mg/mL = 2500mcg/mL. On a U-100 syringe (100 units = 1mL), each unit = 25mcg.

What if the peptide does not fully dissolve?

Let the vial sit upright in the refrigerator for 10-15 minutes, then gently swirl again. Most peptides dissolve completely within minutes. If powder persists after 30 minutes of gentle swirling, the peptide may be degraded.

Peptide Dosage Calculator

Use our free calculator to determine the correct dosage, reconstitution volume, and injection amount for your research peptides.