Before you begin

Reconstitution simply means adding liquid back to a freeze-dried powder. The liquid of choice is bacteriostatic water - water with a small amount of preservative that keeps it stable once opened. Work on a clean surface, with clean hands, and give yourself unhurried time. Nothing about this step rewards rushing.

Let a refrigerated vial come up toward room temperature before you open it. Wipe the rubber stopper with an alcohol swab and let it dry. These are small courtesies that protect a delicate compound.

Adding the water gently

The single most important habit: let the water run down the inside wall of the vial, not straight onto the powder. Peptides are fragile, and a hard stream of liquid striking the powder can damage them. Aim the stream at the glass and let it pool gently over the compound.

Then do not shake. Swirl. Roll the vial slowly between your fingers, or set it down and let it dissolve in its own time. Within a minute or two the solution should turn clear. A clear, particle-free liquid is the sign of a clean reconstitution.

Storing it well

Once reconstituted, a peptide solution lives in the refrigerator. Cold and dark are its friends; heat and light are not. Keep vials upright, away from the freezer wall, and out of the door shelf where the temperature swings each time the fridge opens.

• Lyophilised (unmixed)Stable for a long time when kept cool and dark. The fridge is ideal; a freezer is fine for the powder, never for mixed solution.
• Reconstituted (mixed)Lives in the fridge and is best used within a few weeks. Bacteriostatic water buys you time, not forever.
• Light & heatBoth degrade peptides. An opaque container or a simple box in the fridge keeps light off the vial.
• Never re-freeze solutionFreezing and thawing a mixed vial forms ice crystals that damage the compound. Once it is liquid, keep it liquid and cold.

Signs to respect

Trust the obvious cues. A solution that has turned cloudy, grown floating particles, or changed colour has told you something - set it aside. A clean compound, gently handled and properly chilled, stays clear and quiet until you need it.

Good preparation is unglamorous and entirely worth it. It is the difference between a considered practice and a wasted vial.