Milligrams in the vial, millilitres of water, units on the syringe. One formula connects them, and the calculator on this site does it for you. Here is the logic so you can sanity-check the result.
Both are water. One of them keeps a multi-draw vial usable for weeks, the other is meant to be used once. Which to pick, and how to reconstitute without wasting a vial.
Heat, light, moisture and repeated freeze-thaw cycles are what degrade a peptide. A short guide to storing sealed vials and reconstituted solution the way a lab does.
Two vials can both say 99% and still be different products. Purity, net peptide content and identity are three separate things. Here is how to read them together.
A COA is the lab report behind a vial. Here is what each line means, how to match it to the batch in your hand, and the red flags that should make you walk away.