Humectants pull water into the skin. You might hear “water-loving” or “hydrophilic” tossed around when discussing this ingredient category, and that’s because humectants actually bond to water—and this bond allows the ingredients to travel with water as it gets absorbed into the skin cells. 

It’s important to clarify that humectants are a class of ingredients, which include hyaluronic acid, glycerin, panthenol (vitamin B5), lactic acid, aloe vera, and a few other noteworthy hydrators. The skin makes its own humectants, including hyaluronic acid. But it’s important to use them topically too (especially with age, as our supply declines as we get older).