Alpha hydroxy acids (AHAs) are derived from foods such as sugar cane, milk, apples, grapes, and citrus fruits. The two most common AHAs are lactic acid and glycolic acid. These two acids penetrate the skin effectively and are used in a variety of skin care products.

The main benefit of an AHA is its ability to exfoliate the skin. AHAs improve skin texture and reduce the signs of aging by promoting cell shedding in the outer layers of the skin and by restoring moisture.

It is also believed that alpha hydroxy acids help stimulate the growth of collagen and elastin. Glycolic acids can have varying effects on the skin depending on concentration levels. Higher concentration are more like chemical peels which should only be applied under supervision of a qualified physician. Sun sensitivity and irritation are two major side effects of alpha-hydroxy acids.

Products containing AHAs may increase sensitivity to UV light by as much as 50%, so it is important that a good (broad-spectrum) sunscreen is used. AHAs may also cause the skin to become irritated. Redness, burning and itching are common symptoms. Often times a lower concentration of AHAs will be needed.