Alpha Hydroxy Acids and Chemical Peels
Alpha hydroxy acids in various concentrations are used in chemical peels. The concentration determines who can use it. Alpha hydroxy acid products sold to consumers must have a concentration of less than 10%. Trained cosmetologists can use alpha hydroxy acid products that have a concentration of 20% to 30%. These chemical peels give results that are similar to microdermabrasion - erasing fine lines and giving the skin a smoother appearance with 1 to 3 applications. However, these treatments must be repeated every 3 to 6 months to maintain this skin appearance. Doctors can use alpha hydroxy acid products that have a concentration of 50% to 70%. These treatments also erase fine wrinkles and remove surface scars, but the effects last longer - up to 2 to 5 years. The higher the alpha hydroxy acid concentration used in a chemical peel, the more skin irritation occurs. At the 50% to 70% concentration, a person could expect to have severe redness, flaking, and oozing skin that can last for 1 to 4 weeks.
The Difference Between Alpha and Beta Hydroxy Acids
There is only one beta hydroxy acid - salicylic acid. The main difference between alpha hydroxy acids and beta hydroxy acid is their lipid (oil) solubility. Alpha hydroxy acids are water soluble only, while beta hydroxy acid is lipid (oil) soluble. This means that beta hydroxy acid is able to penetrate into the pore which contains sebum and exfoliate the dead skin cells that are built up inside the pore. Because of this difference in properties, beta hydroxy acid is better used on oily skin with blackheads and whiteheads. Alpha hydroxy acids are better used on thickened, sun-damaged skin where breakouts are not a problem.
Choosing an Alpha Hydroxy Acid
Alpha hydroxy acids are found in a variety of skin care products including moisturizers, cleansers, eye cream, sunscreen, and foundations. Here are some guidelines to use when trying to decide which alpha hydroxy acid formulation to use:
- It is best to pick one product that contains the proper formulation of alpha hydroxy acid to use as your exfoliant, and then choose other skin care products or cosmetics that don't contain alpha hydroxy acids to reduce the likelihood of skin irritation.
- Using an alpha hydroxy acid in a moisturizer base may be the best combination of products.
- Cleansers containing alpha hydroxy acids are not very effective because the alpha hydroxy acid must be absorbed in the skin to work. Cleansers are washed off before this absorption occurs.
- At this time there are no effective products that combine alpha hydroxy acid and sunscreen, because sunscreen is not stable at the pH required to make the alpha hydroxy acid effective.
- Sunscreen MUST be applied liberally when using an alpha hydroxy acid product. The sunscreen should have an SPF of at least 15 for UVB protection and contain avobenzone, titanium dioxide, or zinc oxide for UVA protection.
- Alpha hydroxy acids work best in a concentration of 5% to 8% and at a pH of 3 to 4.
- Unfortunately, cosmetic manufacturers are not required to provide concentration information on the label. As a general rule of thumb, having the alpha hydroxy acid listed as the second or third ingredient on the list makes it more likely it contains the proper concentration.
- The only way to know for sure the pH of a product is to test with a pH strip. Paula Begoun has done this in her skin care product reviews found in her book "Don't go to the Cosmetics Counter Without Me."