Humectants are a class of ingredients that attract and hold water. They occur naturally in your body and skin, as well as make for great topical additions as well. They work so well as skin plumpers because they can pull in moisture into the skin and hold it there throughout the day—and when skin has its fill of water content it appears more supple. Hyaluronic acid, polyglutamic acid, and glycerin tend to be the most popular examples.
In particular, hyaluronic acid holds up to 1,000 times its weight in water: “It functions to retain water, keep our tissues well lubricated, and our skin looking firm and youthful. It also helps to speed up healing by regulating inflammation levels and blood vessel formation, and can increase collagen production, which is another way it can help our skin as we age,” says board-certified dermatologist Jennifer Chwalek, M.D. We recommend finding a serum with multiple sizes of molecular weight, so the different HA molecules can penetrate different layers of the epidermis. Here are our go-to recommendations.
Just be sure to use these correctly: Apply to damp skin (so the molecules have moisture at the ready to bind to) and then seal it in with a thicker, more occlusive option so that the water cannot escape, resulting in transepidermal water loss.