Alpha hydroxy acids (AHAs), beta-hydroxy acids (BHAs) and Polyhydroxy acids (PHAs) are the most common chemical exfoliants. These ingredients may ring a bell, and you may even have a product with the active ingredient in your cabinet already. Either way, it's good to know what it is and, more importantly, what it does:
AHAs
AHAs all work by breaking down the 'glue' that holds skin cells together, allowing dead skin cells to shed and new ones to be produced. Examples include glycolic acid (derived from sugar cane), lactic acid (as you may have guessed, extracted from milk), and malic acid (found in fruits, especially apples).
BHAs
BHA's are oil-soluble molecules that can penetrate into pores. The most common form of BHA is salicylic acid. Salicylic acid has anti-inflammatory and antibacterial properties, making it an ideal tool for people with oily or acne-prone skin.
PHAs
Or better known as Polyhydroxy acids, is a gentler chemical exfoliant. Look for gluconolactone, galactosen and lactobionic acid as these are more common PHAs. PHAs exfoliate dead skin cells from the surface, leading to smoother and more even skin.
Good to know: it is really not necessary to exfoliate every day. In fact, it can irritate your skin because cells need time to renew themselves. Regardless of the instructions on the packaging, start slowly and build up gradually. A helpful tip: oily skin can tolerate more frequent exfoliation than dry, to very dry, skin.