Salicylic acid is a beta-hydroxy acid (sometimes called BHA). If you're familiar with alpha-hydroxy acids (another sort of exfoliant), you'll know that they come in a variety of forms, including glycolic, lactic, and malic acids. (Beta-hydroxy acids are slightly easier to traverse since, while there are several varieties, salicylic acid is the most often utilized in skincare.)
Salicylic acid comes naturally in the bark of willow trees and other plants, but the one found in your cosmetics was most likely produced in a laboratory.
