Hydroxy acids can be available in two basic types – alpha & beta hydroxy acids. These hydroxy acids help in reducing discoloration of the skin, improving acne, perfecting face lines and giving the skin a radiant and healthy glow. For these reasons, they are commonly used in skin care products. Alpha hydroxy acids also known as AHA are a collective of compounds which have been in use to make the skin fresh thousands of years ago. One example is that Cleopatra uses sour milk for bath.
Beta hydroxy acid belongs to a family of organic acids and is not a single substance. These beta hydroxy acids can be found naturally or can be made synthetically. The naturally occurring ones are found in the body, in fruits and in the bark of the willow tree.
These acids have been synthesized in the labs by scientists and it has been proven that they are as effective as the ones found naturally. For this reason they are used in various medicines and other commercial products. The various acids which are a part of the beta hydroxy acid family are salicylic acid, beta-hydroxybutyric acid, 3-hydroxypropionic acid, beta-hydroxy beta-methylbutyrate acid and carnitine.
The main mode of action of beta hydroxy acid is by causing exfoliation of the skin. The dead skin cells from the epidermis are removed and slough off, thus allowing the regrowth of new skin. It helps in improving the fine lines, wrinkles, roughness in skin and mottled pigmentation in photo damaged skin. The effects are seen after daily use for at least 6 months. Skin caring products contain beta hydroxy acid in concentration of 1% to 2% and at pH of 3 to 4.
A layperson might not understand the subtle difference between the alpha & beta hydroxy acids. They both are chemical compounds made up of carboxylic acid and hydroxyl group. The location of the hydroxyl group determines the type of acid. Due to the difference in location of the hydroxyl group, alpha hydroxy acids are water soluble and beta hydroxy acids are oil soluble.
For dry and damaged skin, alpha hydroxy acids should be used; for acne problems on younger and oily skin, beta hydroxy acids should be used.
Various skin care products like moisturizers, cleansers, eye cream, sun-screens and foundations contain beta hydroxy acid. Given below are some pointers when using beta hydroxy acid:
FDA advises that precautions should be taken when using products containing AHAs & BHAs. Some of the precautions are given below:
Note: Salicylic acid is not a true BHA from the point of view of a chemist; however, it is referred to as BHA by cosmetic companies. This can lead to consumers also considering it a BHA.