With all our focus on Cleansing, we’re normally anti-Grunge. But we’ll make an exception for this Boost and its famous grunge song namesake. Glycerin will sink into your skin, moisturizing deep by drawing hydration from the air. As a powerful humectant, it then helps to lock that moisture into both skin & hair. It also softens skin, and helps prevent itching, flaking & frizz on hair.