Alpha hydroxy acids (AHA), like citric acid are a common additive to numerous skin care products including moisturizers, cleansers, toners, and masks. Their primary job in any skin product is as an exfoliant. 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. Citric acids can have varying effects on the skin depending on concentration levels. Higher concentrations 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. Oftentimes a lower concentration of AHAs will be needed.