Alpha-hydroxy acids, beta-hydroxy acids—it can be kind of confusing. Where do they come from, what do they do, and how do you know which one is right for you?
Alpha-hydroxy acids, or AHAs, are derived from fruits and botanicals (although they can be produced synthetically). These are broken down into several acid sub-categoties: glycolic (often from sugarcane), lactic (milk), citric (citrus fruit), malic (often from unripe apples), and tartaric (from grapes and bananas).
Citric, malic and tartaric acids are generally mild and can often be found in over-the-counter skincare products. Most people can tolerate them, unless you have an allergy to any of the fruits they come from.
Lactic acid is mild enough to be done as a peel on almost anyone—unless, again, if you have a milk allergy. It is an excellent choice for dehydrated skin, as lactic acid is a humectant. Because it removes the stratum corneum layer of the skin, it will help with hyperpigmentation. Another benefit is that there is rarely any downtime.
Glycolic acid can be found in various strenghts and pH levels (often found in “professional strength” when used as a chemical peel, but also in over-the-counter strength in daily products). This particular acid is great for stubborn breakouts, congested skin, mild sun damage, and premature aging.
Salicylic acid is a beta-hydroxy acid derived from wintergreen, willow bark or meadowsweet, and is virtually identical to the main ingredient in aspirin. BHAs have a smaller molecular make-up, so these acids can penetrate much deeper into the skin’s layers, often providing stronger results but requiring more downtime for healing, as there tends to be more peeling than with glycolic peels.
Salicylic acid, over time, will help lift hyperpigmentation, clear up more severe cases of acne, smooth rough skin texture, and reverse some signs of sun damage.