- AHA exfoliants are a type of chemical exfoliant.
- They slough off dead cells to gradually reveal brighter, healthier new skin.
- Common AHAs include glycolic acid, lactic acid and mandelic acid.
- They are safe for all skin types, with a few caveats.
Chemical exfoliants fall into several categories determined by their molecular properties. One category is AHAs, the most popular type of chemical exfoliant. AHA exfoliants include multiple types of acids of varying strengths. Your skin type and the skin concerns you need to address determine the right AHA exfoliant for you.
What is an AHA?
AHA is short for alpha-hydroxy acid, a type of water-soluble acid. Most are derived from fruit sugars. AHAs chemically exfoliate by loosening the bonds that hold dead cells to the skin’s surface.
They are most effective at treating mild hyperpigmentation, enlarged pores, fine lines, wrinkles and uneven skin tone.
This acid has a small molecular size, meaning its molecules can easily penetrate the pores of your skin to exfoliate deeply.
Lactic acid, another popular AHA, is derived from the lactose in milk. It is considered milder than some other AHAs but still has significant exfoliating properties.
Extracted from apples, malic acid is not a very effective exfoliant on its own. However, it can make other AHAs more effective when used in combination with them. For this reason, malic acid is most often found alongside other exfoliators in skin care products.
Mandelic acid has a larger molecular size, making it a slow-acting exfoliant that is gentle enough for sensitive skin types.
Whereas many AHAs can cause discoloration in dark skin at higher concentrations, mandelic acid has been demonstrated to effectively and safely lighten hyperpigmentation in dark skin when used in combination with salicylic acid.
Though less common than other AHAs, tartaric acid is used to treat sun damage and acne and is derived from grapes.
How Do AHAs Exfoliate?
When applied topically, AHAs break up the bonds between dead cells in the stratum corneum, the protective outermost layer of skin. Once those bonds are weakened, the cells easily slough off.
Removal of these dead skin cells promotes the renewal of healthier cells beneath. The skin revealed shows lightened hyperpigmentation, less prominent fine lines, fewer blemishes and a softer, smoother overall appearance.
Additional benefits of AHAs include increased moisturization, collagen production and skin thickness.
Are AHA Exfoliants Right for You?
AHAs are considered safe for all skin types. However, your skin type determines how often and in what concentrations you should use them, as some skin types are more tolerant of AHA’s effects than others.
For sensitive skin
Chemical exfoliants are often more effective than physical exfoliants for this skin type because they do not require scrubbing, which can irritate sensitive skin.
However, as sensitive skin easily reacts to many skin care products, individuals with this skin type should exercise caution when applying AHAs.
Find a product that contains a low percentage of the active ingredient (less than 5%) and use one to two times a week. Look for products containing lactic acid or mandelic acid, the mildest of the AHAs. If you are using a rinse-off product, aim for the lower end of the recommended leave-on time.
Your skin may gradually build up a tolerance to AHAs, but if you experience any redness or irritation, decrease your frequency of use.
For dry skin
AHAs work well for dry skin as they address issues such as fine lines, sun damage and roughness commonly experienced by this skin type. However, as the protective barrier of dry skin is sometimes compromised, be careful not to over-exfoliate and strip your skin of further moisture.
Lactic acid has moisturizing properties and has been shown not to damage the epidermal barrier when applied topically.
For acne-prone skin
Oily skin that’s prone to breakouts can generally tolerate glycolic acid well. In addition to deeply exfoliating, glycolic acid has antimicrobial properties and has been demonstrated to improve mild acne.
Due to its anti-inflammatory properties, tartaric acid is also commonly recommended for acne-prone skin.
How to Use AHA Exfoliants
When using an AHA exfoliant, follow the included directions to know at what stage of your skin care routine it should be applied. If there is a recommended leave-on time, you may wish to err on the shorter side to test your skin’s reaction. If you start to feel any burning or tingling, wash the product off immediately.
As a rule, AHAs are best used at night so that your skin has time to recover and rejuvenate while you sleep.
Regular AHA use increases your skin’s sensitivity to the sun. Apply a moisturizer containing a sunscreen of at least 30 SPF every morning while using AHA products.
How often should you use AHA exfoliants?
The frequency you apply AHAs depends on both your skin type and the type of products you use.
Many products such as exfoliating cleansers, wipes and toners indicate that they are safe for daily use. However, you’ll likely want to only use them a few times a week at first to allow your skin to build a tolerance. Individuals with dry or sensitive skin may find their skin can only tolerate these products a few days a week, even after several months of use.
Some products, such as serums, contain high concentrations of active ingredients and should only be used a few times a month.
AHAs vs. BHAs
Whereas AHAs are water-soluble, beta-hydroxy acids or BHAs are oil-soluble. The property enables them to penetrate clogged pores and dissolve sebum, the oil naturally occurring in your skin.
Because of this property, BHAs are effective at reducing acne and drying out excess oil on the face. The most common BHA is salicylic acid.
Neither AHA or BHA exfoliants are intrinsically more effective than the other; whether AHAs or BHAs work best for you depends entirely on your skin’s needs.
Retinoids offer numerous skin care benefits and address many of the same issues as AHAs. They can reduce signs of aging, including fine lines, wrinkles and uneven skin tone. Retinoids can also treat acne symptoms.
If you are not interested in retinoids and your skin does not tolerate acids well, using a gentle facial scrub once a week can be an effective means of exfoliation. Try a commercial product or create a scrub at home with a DIY recipe customized for your skin.
AHAs or alpha-hydroxy acids are exfoliating acids usually derived from fruit sugars. The most common AHAs are glycolic acid, lactic acid, mandelic acid, malic acid and tartaric acid.
Dry skin types benefit most from glycolic or lactic acid. If you have sensitive skin, lactic or mandelic acid are the least likely to cause a reaction in your skin. Individuals with acne-prone or oily skin may use mandelic, glycolic or tartaric acid.
As an alternative to AHAs, BHAs, another class of chemical exfoliant, may be particularly effective for oily skin. Retinoids are another solution for many of the skin issues that AHAs seek to correct.
If your skin cannot tolerate any acids, consider a mild facial scrub to keep your skin exfoliated and feeling clean.
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