Beauty Wonkette's CliffsNotes Guide to Acid 101

Acids can be the most important part of your skin-care routine. That is, as long as you know your ferulic from your salicylic. Indeed, all acids are not created equal, which is why it's worth it to learn the real deal on each one and, in turn, avoid unnecessary reactions (not to mention, never shell out big bucks for a product that's totally wrong for your skin type ever again).  After consulting with several of Beauty Wonkette's favorite dermatologists, we present a reasonable approximation of which acids will brighten us up, zap our acne, and generally leave our mugs as smooth as a baby's butt. Read on and bring this along as a cheat sheet the next time you go skin-care shopping.

Salicylic Acid 
Salicylic acid also goes by the name beta hydroxy acid.  It is a keratolytic agent (meaning that it removes the top layer of skin when pores are clogged). BW's derm recommends the ingredient for oily skin, but reports that it can also be used on drier or sensitive skin, as long as it is combined with hydrating ingredients, such as those found in Aveeno's Clear Complexion line. A warning: Pregnant women shouldn't use products that contain salicylic acid, as salicylates have been linked to birth defects.

Alpha-Hydroxy Acid
Alpha-hydroxyl acids are a group of acids named based on their chemical appearance. In this grouping: lactic acid (which is derived from milk), glycolic acid (derived from sugar cane), citric acid (from citrus fruits), and tartric acid (from grapes). AHAs have multiple good effects on the skin: they are primarily used as chemical exfoliants, but they have also shown to promote collagen synthesis and reduce hyperpigmentation.

AHAs can be beneficial for almost any skin type. If you have sensitive skin, start with a mild daily lotion to test its effects (BW's derm likes the NeoStrata line, which was the first of its kind to make AHAs user-friendly).

Hyaluronic Acid
Hyaluronic acid is the ingredient that you want to turn to when your skin becomes drier than the Sahara (probably right around this time of the year), as the molecule can hold up to 1,000 time its weight in water. This ingredient actually has the ability to pull moisture from the air down through the stratum corneum (or outermost layer of the skin) so that skin stays supple.

Hyaluronic acid is obviously a great pick in moisturizers, but look out for it in treatment products as well — the addition of hyaluronic to a typically irritating ingredient like retinol can ease the burn.

Ferulic & Alpha Lipoic Acids
These two ingredients are antioxidants — meaning that they reduce the amount of free radicals wreaking havoc on your skin (a result of your bod dealing with environmental stressors such as sun damage and pollution). Plus, these puppies aid in collagen production so your skin will be plump and protected.