Are both AHA and BHA exfoliants?

There are two primary ways to exfoliate skin, either with alpha hydroxy acids (AHAs), or with beta hydroxy acid (BHA). There is only one BHA (beta hydroxy acid) and that is salicylic acid, but there are a variety of AHAs. The five major types of AHAs that show up in skin-care products are glycolic, lactic, malic, citric, and tartaric acids. The primary difference between AHAs and BHA is that AHAs are water-soluble, while BHA is lipid-(oil) soluble. This unique property of BHA allows it to penetrate the oil in the pores and exfoliate accumulated skin cells inside the oil gland that can clog pores. BHA is best used where blackheads and blemishes are the issue, and AHAs are best for sun-damaged, thickened, dry skin where breakouts are not a problem.