NEW 1 oz (30ml) Lactic Acid Lactic acid and glycolic acid are both organic alpha hydroxy acids (AHA), which are commonly used in chemical exfoliation treatments. Physical exfoliation such as microdermabrasion is used on a daily to biweekly basis to scrape away the dead surface skin cells. Chemical exfoliation works similarly, however, it is more aggressive and removes more than just the top layer of cells. These acids work by penetrating the skin and removing more dead cells, revealing the new, youthful cells underneath. Recently, lactic acid has become more popular as it seems it is more effective than glycolic acid while being less irritating. Because it is a smaller molecule, glycolic acid penetrates the skin more readily, which is why dermatologists have long thought that glycolic acid is better for chemical exfoliation. However, since glycolic acid penetrates the skin more effectively, it also comes with a fair amount of irritation, so it is milder than glycolic acid. Lactic acid is a slightly larger molecule, so it does not penetrate quite as deep, meaning less irritation. Additionally, lactic acid has been found to stimulate cell turnover and renewal much more quickly than glycolic acid, and at percentages higher than 5%, lactic acid has been found to hydrate and whiten the skin. Chemical exfoliation is used to treat a variety of skin conditions such as acne, dry skin, dark spots, wrinkles, in-grown hairs, and keratosis. The percentage strength that should be used differs from person to person. Lower percentages (up to 30%) should be used for periodic use or those who are just starting out. Higher percentages should be used with caution, and generally are used on lower extremities.