Whether you’re a skin care pro or a curious beginner, you’ve probably scanned the ingredients list of your favorite creams , cleansers and sheet masks wondering what it all means and what they can do for your skin. Or, perhaps, you’ve stumbled upon a new “It” ingredient on social media and want to know if it’s worth the money. To help you navigate the world of complex skin care terms, I created a glossary of ingredients, guided by board-certified dermatologists and our extensive past coverage .