And while many top vitamin C serums come in a glass bottle with a dropper, Castilla says those with airless pump bottles will stay active longer. Store your serum away from the sun and don’t ...

For a vitamin C serum to be effective, dermatologists say there are a few key things to consider: Want more from NBC Select? Sign up for our newsletter, The Selection, and shop smarter.

It helps protect delicate skin from the sun while battling fine lines and dark spots, fans say — wins all around.