Keep peptide vials refrigerated at all times to reduce peptide bond breakdown. DO NOT FREEZE. Most peptides, especially shorter ones, can be preserved for weeks if careful.
Always swab the top of the vial with an alcohol wipe, rubbing alcohol or 95% ethanol before use.
Before drawing solution from any dissolved peptide vial, fill the pin with air to the same measurement you will be filling with solution, ie. if you plan to take 0.1 ml, first fill the pin with 0.1ml of air, push the air into the vial, and then draw the peptide back up to the 0.1 ml marker. Doing so will maintain even pressure in the vial. Always remember to remove air bubbles from the pin by flicking it gently, needle side up, and pushing bubbles out. In addition, push out a tiny amount of solution to ensure there is no air left in the metal tip.