Alpha Hydroxy Acids (AHA) is really a family of acids. Glycolic is the most widely used because of its small molecular structure. AHA is one of the safest methods of skin renewal. Their effectiveness depends on the type and concentration of the AHA, its pH (acidity) and other ingredients in the product. AHAs become effective at concentrations of about 7% to 8% with a pH of 3.5 to 4.0. Many AHA-containing products have very little skin renewal effects, because the AHA concentrations are too low and the pH too high. The marketed purposes are mainly to smooth fine lines and surface wrinkles, to improve skin texture and tone, to unblock and cleanse pores, to improve oily skin or acne and to improve skin condition in general. In reality, they do increase the turnover of the skin cells and enhance the rebuilding of collagen and elastin, plus improve the internal moisture-holding properties of GAGs and proteoglycans. With long-term use, AHAs alleviate fine to moderate wrinkles and remove many skin lesions, such as weathered skin, freckling, blotchy pigmentation, sun damage, age spots, mild acne scars, benign overgrowths of skin and flat warts. They appear to work by causing an increased skin peeling of the lesion plus an irritation around the lesion. In time, the lesion becomes smaller and is replaced by normal, healthy skin.