Alpha hydroxy acid, also called AHA, is a type of acid derived from a natural source, such as citric or lactic acid. Glycolic acid is an AHA derived from sugar cane. Home exfoliating products, such as lotions or cleaners, use AHA to rejuvenate and freshen skin. Professional chemical peels use stronger AHA solutions that remove the topmost layers of skin to reduce fine wrinkles and sun damage. Over-the-counter products containing 12 percent or less glycolic acid and other AHAs are usually gentle enough for daily or weekly use.
Everyone's skin is different, and some people have stronger reactions to AHA and glycolic acid. Irritation might include redness and swelling. If it's the first time you're using a product containing AHA, do a patch test on your inner elbow the day before you try the product on your face. Do not use the product if there is any sign of irritation from the patch test.
If you have a reaction on your face from 12 percent glycolic acid, stop using the product. Consider using a product with a lower concentration of AHA or glycolic acid.
A mild burning or stinging sensation is a common side effect of glycolic acid and AHA products. Usually the stinging is temporary and will disappear when you wash the product off. If the burning doesn't bother you much, try using the product less frequently until your skin gets used to it. If your skin still burns after washing the product off, try switching to a lower concentration.
Your skin may peel after using glycolic acid or AHA, especially if you are using other exfoliating products or acne medications. White patches sometimes appear on areas of skin that are about to peel. Avoid picking or pulling at peeling skin, or you risk scarring and infection.
Itching is a less-common side effect of AHA and glycolic acid. In many cases, itching accompanies peeling. Soothe itchy skin with a cold compress. Apply a moisturizer if your skin feels tight and itchy.
Since glycolic acid and AHA remove dead skin and some of the upper layers of skin, photosensitivity is a very common side effect. You may sunburn easily from very little sun exposure or from using a tanning bed. After using any AHA on your skin, protect yourself with a sunscreen that's SPF 15 or higher. Getting a sunburn after using AHA or glycolic acid increases your chance of permanent sun damage.