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The alpha hydroxy acid family of skincare ingredients (or AHAs) has a long history that dates back to ancient Egypt when sour milk was used to improve the smoothness and appearance of the skin1 —and we now know that lactic acid was the compound responsible for the visible and palpable improvement. In modern times, glycolic acid helped bring AHA skincare into the mainstream after being extensively studied throughout the 1900s and becoming widely available in the late 1980s.2
Using AHA for skin exfoliation helps improve the appearance of fine lines and wrinkles. skin discoloration, and rough texture by eliminating the buildup of dull, dead cells and keeping fresh, healthy cells on the skin’s surface.
What is an alpha hydroxy acid?
AHAs are acids that are found naturally in fruits and plants such as sugarcane, citrus, apples, and grapes, and they can also be a byproduct of the fermentation associated with milk and vegetables. Today, many alpha hydroxy acids are synthesized in labs.
How does AHA skincare work?
Alpha hydroxy acids provide chemical exfoliation that accelerates the skin’s natural shedding of dead cells. AHA skincare works by dissolving the bonds that hold dead cells on the skin’s surface, which makes it easier for them to flake off. In addition, skincare products that are formulated with alpha hydroxy acid help promote skin renewal by increasing the rate of cellular turnover as well.
AHA benefits for specific skin concerns
Using AHA for skin exfoliation helps improve the appearance of fine lines and wrinkles, skin discoloration, and rough texture by eliminating the buildup of dull, dead cells and keeping fresh, healthy cells on the skin’s surface.
Types of alpha hydroxy acids
There are several ingredients in the alpha hydroxy acid family, and their exfoliating effects can have different benefits for various skin types and concerns. Alpha hydroxy acids can be found in cleansers, toners, serums, and moisturizers, and they are used at varying concentrations in professional treatments such as chemical peels and Hydrafacials as well.
Glycolic acid: This alpha hydroxy acid occurs naturally in several plants and fruits including sugar cane, grapes, sugar beets, and more. Although all skincare-based exfoliants work exclusively on the skin’s surface, glycolic acid has the smallest molecule size as compared to other AHA skincare ingredients, which allows it penetrate more deeply into the uppermost layers of skin. Proven to increase skin hydration in addition to providing exfoliation, skincare professionals often recommend glycolic acid for skin concerns such as visible signs of aging and sun damage.
Lactic acid: This natural byproduct of dairy fermentation offers gentle AHA benefits that can generally be tolerated by sensitive skin due to its larger molecule size. This alpha hydroxy acid is also a component of the skin’s natural moisturizing factor (NMF), which supports benefits of lactic acid for skin hydration. Studies have shown the value of using lactic acid for skin discoloration as well.
Citric acid: Found naturally in citrus fruits, the AHA benefits of citric acid include promoting cell turnover to exfoliate and smooth skin. This alpha hydroxy acid can also be used as a non-toxic preservative to protect the stability of skincare products and help balance their pH.
Malic acid: Derived from apples and cherries or produced in a lab, malic acid has a larger molecule size than most other exfoliating alpha hydroxy acids, which means it does not penetrate the skin as deeply and is less likely to cause irritation in sensitive skin.
The difference between AHA and BHA
They key difference between AHA and BHA is that alpha hydroxy acids are water-soluble and beta hydroxy acids are oil-soluble. This BHA attribute allows them to refine the skin’s surface and dissolve sebum to decongest pores. BHAs are especially beneficial for those with oily or blemish-prone skin, and beta hydroxy acids are appropriate for skin of color and those with sensitive skin as well.
Similar to AHA skincare, beta hydroxy acids help improve the appearance of visible signs of aging, including fine lines, wrinkles, dullness, and uneven skin tone, and can be found in cleansers, toners, serums, and moisturizers as well as office-based chemical peels. Beta hydroxy acids include salicylic acid and lipo-hydroxy acid (LHA), a proprietary SkinCeuticals ingredient that provides cell-by-cell exfoliation and helps promote cell turnover.
SkinCeuticals AHA skincare
LHA Cleansing Gel and Toner: Formulated with alpha hydroxy glycolic acid for skin refinement along with beta hydroxy salicylic and lipo-hydroxy acids to decongest pores, these products start any skincare regimen for aging, oily, or blemish-prone skin with an exfoliating, skin-brightening, AHA and BHA boost.
Simply Clean Cleanser: Ideal for normal, oily, and combination skin, this gel-based cleanser contains an alpha hydroxy fruit acid blend for gentle exfoliation that reveals softer, smoother skin—and it effectively removes long-wear and waterproof makeup.
Conditioning Toner: Designed to soften and refresh the skin, this pore-minimizing toner with AHA and BHA is ideal for those with normal and oily skin who are concerned about visible signs of aging and discoloration.
Glycolic Renewal Cleanser: Featuring 8% glycolic acid for skin benefits that include improved surface texture and radiance, this soft-foaming alpha hydroxy gel cleanser effectively exfoliates without over-drying the skin.
Glycolic 10 Renew Overnight: This nighttime treatment offers the AHA benefits of 10% glycolic acid to improve the appearance of visible signs of aging and discoloration, along with 2% phytic acid and a triple-action soothing complex to promote cellular renewal, skin clarity, and overall radiance.
Blemish + Age Defense: With a combination of AHA and BHA glycolic, lactic, salicylic, and lipo-hydroxy acids, this oil-free serum is specifically designed to simultaneously minimize clogged pores and breakouts while improving the appearance of fine lines, wrinkles, and uneven skin tone.
The importance of sun protection when using AHA skincare
Alpha hydroxy acids help minimize the buildup of dead cells on the skin’s surface to reveal radiant, healthy-looking skin—but removing this uppermost layer of skin can leave the skin more vulnerable to UV rays. Although sunscreen should be the final step in any skincare regimen every day, it’s especially important to use broad-spectrum sun protection daily when using AHA skincare.
To discover the ideal alpha hydroxy acid skincare products for your unique skin, use our online Regimen Finder, visit one of our SkinCeuticals SkinLab locations, or schedule an appointment with a SkinCeuticals Skincare Professional for a one-on-one consultation .
Next: What is the difference between physical and chemical exfoliation?
