Reconstituting research peptides correctly

A lyophilised peptide is a fragile powder held under vacuum. Everything you do in the first two minutes after breaking that seal decides how much intact peptide you still have a week later.

Start with bacteriostatic water at room temperature. Cold solvent hitting a cold cake slows dissolution and tempts people to agitate the vial, which is where most damage happens. Angle the needle against the glass wall so the stream runs down the side rather than jetting directly into the powder.

Never shake. Swirl gently, or simply let the vial stand for a few minutes — most compounds in this catalogue dissolve on their own without help. Foaming is a visible sign of shear stress, and shear stress means fragmented sequences.

Account for dead volume. A standard insulin syringe holds a small residual amount in the hub and needle, so a nominal 1ml draw is rarely a true 1ml. When accuracy matters for a study, weigh your draws once and record the real figure.

Once reconstituted, store at 2–8°C, keep the vial upright, and protect it from light. Note the reconstitution date on the label — solution stability is measured in weeks, not months.