What to look for on the label: Glycolic, malic, citric and lactic acids. Glycolic is the most commonly used because it yields good results with little irritation.
For best results: Add an AHA lotion or cream to your daily skincare regimen, or do an at-home AHA peel once a week (or more, if your skin isn't too sensitive). Many dermatologists recommend using an AHA lotion in the morning so your nighttime treatment (whether a retinoid, basic moisturizer, or both) can penetrate more effectively. Both retinoids and AHAs exfoliate the skin, so ease into a regimen that includes the two to avoid redness and peeling. AHAs are great to use on your neck (where the skin is generally too thin to tolerate a retinoid), and can smooth irritation like keratosis pilaris (those little bumps you might have on the backs of your arms) as well as ashy elbows and knees.
You should know: Cleansers containing AHAs aren't in contact with the skin long enough to have any effect. To get results, invest in a cream instead.
Peter Thomas Roth Max Complexion Correction Pads ($36; peterthomasroth.com)
Beauty Rx Skincare by Dr. Schultz Daily Exfoliating Body Therapy Lotion ($50; beautyrx.com)