Do you know how to decipher the ingredients label on your moisturiser? Or whether you should be using retinol? Or what the difference is between AHAs and BHA? Relax and let the Vogue Skincare Alphabet break it down. What are they? AHAs are alpha hydroxy acids - a class of chemical compounds that can be either naturally occurring or synthetic. Many are derived from organic sugars, with glycolic acid (from sugar cane) and lactic acid (from milk) the best-known and best-researched ...