Hydroxy Acids

HYDROXY ACID skin care is one of the oldest and newest market options in skin care. Centuries ago, women applied old wine, sour milk, lemon juice and other acidic products to help reduce the signs of aging. Today these products are more refined and are known as hydroxy acids.

Trying to make sense of the hydroxy acids is very confusing with all of the new and innovative products on the market. Basically, hydroxy acids penetrate the top layers of the skin, epidermis and upper dermis, to achieve exfoliation (sloughing of old skin cells). Exfoliation stimulates the skin and healthy cells are regenerated. The effect essentially is "anti-aging." The skin is smoother and softer with an overall lessening of fine wrinkles and skin discoloration.

The hydroxy acids are also used to improve scaling, precancerous growths (actinic keratoses) on sun-damaged skin. In addition, there is also great benefit with acne. Dead skin cells are exfoliated, opening the pores. Since hydroxy acids are in an infinite array of products, how does one choose the correct formulation for his or her skin condition? The following is a brief explanation of the advantages in each category:

Alpha hydroxy acids derive their name from the molecular composition of the acid. These products include the subcategories of glycolic, malic and citric acids. These acids dissolve easily in water and can penetrate readily into the epidermis and upper dermis. The overall effect is upper skin exfoliation. Oily skin must be cleansed prior to application in order for these acids to be effective.

Beta hydroxy acids, namely salicylic acids, are also named from the molecular composition of the acid. These acids are unique in that they are readily absorbed by the fat properties of the skin. Skin is composed of water and fat molecules that limit penetration from the outside. Different from alpha hydroxy acid, this acid is unique in that it can penetrate into the pores of the skin. This helps clear the pores and exfoliate the skin. Beta hydroxy acid also has anti-inflammatory properties that result in less irritation, burning and stinging.

Currently there are new formulations of hydroxy acids being researched that are combinations of alpha and beta hydroxy acids. Ideally, it would be nice to have a combination product that has the advantages of both hydroxy acids.

Alpha hydroxy acids, specifically glycolic acid, are available in concentrations between 2% and 20%. They are found in facial washes, toners, moisturizers, sunscreens and a wide variety of other products. Beta hydroxy acids are available in concentrations up to 2% and are also found in many commercial products. Although the higher concentrations can be more effective, there are other factors to consider when evaluating and purchasing a hydroxy acid.

The effectiveness of the hydroxy acid lotion or cream is determined by its acidity. Chemically speaking, these products work better in an acidic environment. The higher acid concentrations are not necessarily the most potent. The effectiveness is highly dependent on the formulation.

As a consumer, despite the labeling, it is impossible to know the chemical composition or acidity of a given product. This is why it is important to purchase widely used or name brand products from reputable manufacturers. Products cannot be compared based on the labeling.


The hydroxy acids are used widely for exfoliation, sun damage and acne. Watch the use of these products, as they can cause irritation to the skin. A red flaky face is not necessarily a healthy face, not to mention an unhealthy presentation.

Hydroxy acid washes are very effective for cleansing and exfoliating the skin. This should be done at least twice daily. Hydroxy acid lotions and creams should be applied at least once daily. Some individuals can use these products twice daily without irritation. Individual preference should dictate morning or nighttime application.

Some scientists question simultaneous use of hydroxy acids with retinoic products and vitamin C. (Retinoic acid and Vitamin C are also used for sun damage.) Most people use the hydroxy acids in the morning and retinoic acid and Vitamin C in the evening. It is essential to use a good sunscreen (SPF 15 or greater), giving UVA and UVB coverage. Remember progress is made in small steps. Used regularly, and over time, hydroxy acids are beneficial and very effective for daily skin maintenance.

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