Reconstituting lyophilized peptides

Most research peptides ship lyophilized — freeze-dried into a small pellet or film at the bottom of the vial. In this state they are stable and travel well. To work with them, you reconstitute: you add a measured volume of bacteriostatic water and let the peptide dissolve.

The volume of water you add sets the concentration of the resulting solution — more water means a more dilute solution, less means the opposite. Record the volume used so the concentration of every vial is documented for your records.

Add the water slowly, letting it run down the inside wall of the vial rather than jetting directly onto the pellet. Then swirl gently. Never shake — agitation can shear fragile peptide chains. Give it a minute; most compounds go into solution quickly and clearly.

Once reconstituted, keep the vial refrigerated at 2–8°C and protected from light. As a general research rule of thumb, a reconstituted vial is used within about four weeks, though this varies by compound. Lyophilized, unopened vials keep far longer in the fridge or freezer.