Reconstitution is the process of dissolving a lyophilised (freeze-dried) peptide powder into a liquid solution ready for research use. It sounds simple ā but there are a handful of critical mistakes that can degrade or destroy your peptide before you even begin. This guide covers everything you need to do it right.
What You'll Need
- Your lyophilised peptide vial ā kept refrigerated or frozen until use
- Bacteriostatic water (BAC water) ā the gold standard diluent for peptide reconstitution
- Insulin syringes ā for drawing and injecting the BAC water into the vial
- Alcohol swabs ā to sterilise the rubber stoppers before puncturing
Do not use regular tap water, saline, or sterile water as your primary diluent. BAC water contains 0.9% benzyl alcohol which inhibits bacterial growth, keeping your reconstituted solution stable for weeks when refrigerated. Regular sterile water has no preservative and degrades rapidly once opened.
Step-by-Step Reconstitution Process
Step 1 ā Let the Vial Reach Room Temperature
Remove the peptide vial from the refrigerator and allow it to sit at room temperature for 15ā20 minutes before opening. Injecting cold liquid into a cold vial creates unnecessary condensation and thermal stress. Never microwave or apply heat to a peptide vial.
Step 2 ā Swab Both Stoppers
Wipe the rubber stopper on both the peptide vial and the BAC water vial with a fresh alcohol swab. Allow them to air dry for 30 seconds ā do not blow on them or wipe them dry. Puncturing a wet stopper can introduce alcohol into your solution.
Step 3 ā Draw Your BAC Water
Using a clean insulin syringe, draw the volume of BAC water you've calculated (see our peptide calculator guide). A standard starting point for most 10mg vials is 1ā2mL of BAC water.
Step 4 ā Inject Slowly Down the Side of the Vial
This is the most critical step. Do not squirt the water directly onto the peptide powder. Instead, angle the needle so it touches the inner glass wall of the vial, and allow the water to run slowly down the side and onto the powder below. This prevents physical disruption of the fragile peptide bonds.
Apply gentle, steady pressure on the plunger. The entire injection should take 15ā30 seconds ā not a quick push.
Step 5 ā Never Shake the Vial
Once the water is added, do not shake the vial. Shaking creates mechanical stress that can break peptide bonds and reduce potency. Instead, gently roll the vial between your palms, or swirl it very slowly. If the powder does not dissolve immediately, place it in the refrigerator for 30 minutes ā it will dissolve on its own.
Step 6 ā Inspect the Solution
A properly reconstituted peptide solution should be clear and colourless (some peptides produce a very slight yellow tint ā this is normal). If the solution is cloudy, milky, or contains visible particles, do not use it.
Storage After Reconstitution
Once reconstituted, your peptide solution should be:
- Refrigerated at 4Ā°C ā not frozen
- Used within 4ā6 weeks ā BAC water extends stability but the peptide does degrade over time
- Kept away from light ā store in the original vial or a dark location
- Never refrozen after reconstitution ā freeze-thaw cycles degrade peptide bonds
What If the Powder Won't Dissolve?
Some peptides ā particularly those with complex sequences ā can be slow to dissolve. If your peptide hasn't fully dissolved after gentle swirling:
- Refrigerate for 30ā60 minutes and check again
- Try adding a small additional volume of BAC water (0.5mL) and swirl gently
- Some researchers add a small amount of dilute acetic acid (0.1%) for particularly stubborn peptides like GHK-Cu ā check specific guidance for your compound
Common Mistakes to Avoid
- Shaking the vial ā always swirl, never shake
- Using sterile water instead of BAC water
- Injecting water directly onto the powder instead of down the glass wall
- Reconstituting while the vial is still cold
- Storing reconstituted peptides in the freezer
- Using a vial that has been left unrefrigerated for more than a few hours
ā For in-vitro research and laboratory use only. Not for human consumption.