Alpha and Beta Hydroxy Acids: What's the Difference?

What is a hydroxy acid?

Both AHAs and BHAs fall into the group of skincare ingredients known as chemical exfoliants, which simply means they exfoliate dead skin cells from the skin's surface via chemical means rather than physical rubbing and scrubbing. Chemical exfoliants are generally gentle acids (often, but not always from fruit) or enzymes.

You'll find both types of hydroxy acid featured in many different types of skincare product, including cleansers, toners, moisturisers, face masks, and serums. The removal of dead skin cells can be used to help various skin conditions, which include:

• helping prevent blemishes in mild acne-prone skin

• reducing the appearance of visible signs of ageing (such as fine lines, wrinkles, and sun aged skin

• helping dull, discoloured skin to appear more radiant

• refining the appearance of pores

• removing makeup, stubborn residues, and external aggressors.

Regular exfoliation can also improve the effectiveness of skincare products you’re using for other concerns, by helping expose fresh, newer surface cells to their benefit.

What's the difference between AHAs and BHAs?

The difference between AHAs and BHA's The mechanisms by which they exfoliate differ (along with some of their properties), and this impacts the skin concerns they are best suited to support.

Although both alpha hydroxy acid and beta hydroxy acid can deeply and effectively exfoliate the skin, the concentration used will also vary based on which skin conditions are being targeted.

Alpha hydroxy acids

All alpha hydroxy acids are naturally occurring, water soluble, organic acids, found in fruits and plants. Examples include citric acid, lactic acid, malic acid and glycolic acid. In skincare, these are typically used for:

• Minimising the appearance of mild hyperpigmentation, such as age spots

• Helping pores to appear smaller

• Reducing visible signs of ageing, such as smoothing fine lines and surface wrinkles

• Helping skin tone appear more even

Alpha hydroxy acids are especially suited to dry skin types. Note: anyone with extremely dry or sensitive skin may need to progressively work up to daily use, to prevent skin sensitivities.

Alpha hydroxy acids also tend to cause increased sun sensitivity, so it's important to apply a broad-spectrum, high-SPF sunscreen in the mornings, when using them.

Glycolic acid

Glycolic acid is the smallest alpha hydroxy acid, and considered to have the greatest rate and degree of skin penetration. A glycolic acid peel is a chemical peel using glycolic acid as the primary exfoliant in the formula. Performed by a skincare professional, these treatments exfoliate and promote skin cell renewal. Studies also suggest topical glycolic acid can stimulate production of collagen

Beta hydroxy acids

Found in plants, tree bark, fruit and some dairy products, beta hydroxy acid examples include salicylic acid, lipo-hydroxy acid (LHA),and benzoic acid. In skincare, they are used as gentle chemical exfoliants and to help brighten the complexion by promoting skin cell turnover.

Because of their oil-solubility, BHAs can also be used to dissolve excess sebum (natural skin oil) and target blemishes such as blackheads and whiteheads.

BHAs are most commonly used for:

• Mild acne-prone skin

• Skin prone to visible redness

• Combination and oily skin types

Beta hydroxy acids are generally appropriate for all skin tones as well as anyone with sensitive skin.

Salicylic acid

Salicylic acid is a BHA that's regularly included in products formulated for oily or blemish-prone skin. Its oil-solubility enables salicylic acid to penetrate into the pores and exfoliate them from within.

AHAs or BHAs? When & how to introduce them to your skin.

The first thing to note is that one type of hydroxy acid isn't universally superior to the other. Either type can be a great option for a variety of skin care concerns, or even be used in tandem.

The first question to ask when deciding whether to use an AHA or a BHA is, “What's my main skin concern?” As we've seen above, your answer will guide your decision on which is more appropriate.

Depending on your skin type and aims, you can also use AHAs and BHAs together. In fact, healthcare professionals often recommend people with mild blemish-prone or an oily skin type to combine the two.

If you do decide to combine both AHAs and BHAs in your regimen, we recommend you choose products that contain your required ingredients in a ready-optimised formula. Or alternate their use, with one type of hydroxy acid in the morning and another at night, which will minimise skin irritation or excessive dryness.

Discover a selection of CeraVe skincare products containing AHAs and BHAs below:

CeraVe AHA and BHA products to try

CeraVe skincare products are cosmetic formulations designed to effectively address various skin concerns. A number of them are formulated with BHAs or AHA/BHA blends:

• Blemish Control Cleanser for mild blemish-prone skin is formulated with 2% salicylic acid to target blemishes and visibly reduce the appearance of blackheads. It also assists with preventing future breakouts, while supporting the skin moisture barrier with 3 essential ceramides.

• For a cleanser that removes makeup, try Ceramides Hydrating Cream-to-Foam Cleanser. Providing double the BHA action with both salicylic acid and benzoic acid, it's formulated with three essential ceramides, amino acids and hyaluronic acid.

• If you're looking for an AHA/BHA blend after cleansing, turn to Blemish Control Gel. The BHA salicylic acid helps target blemishes and prevent future breakouts, whilst AHAs lactic and glycolic acids work to even and soften the skin.

Is it okay to use AHAs and BHAs every day?

With alpha hydroxy acid, our advice is to start out using them just a couple of times a week, to minimise the likelihood of skin sensitivities. After your skin has developed a level of tolerance to the ingredient, you can if desired increase the frequency of use to alternate days or even daily.

BHAs tend to be a little more gentle on the skin, and suitable for daily use; however, using no more than two to three times a week is advisable once again when first starting out.

Keep in mind that for most skins, exfoliation 2-3 times per week is perfectly adequate, and use of AHAs and/or BHAs more often than that can prompt unwanted side effects.

Also note that AHAs (and to a slightly lesser extent, BHAs) tend to make your skin more sensitive to the sun, so use of a high-SPF, broad spectrum sunscreen every morning, with regular reapplication through the day, is a daily essential when using these ingredients.

What shouldn't you use before or after AHAs or BHAs?

Healthcare professionals don't recommend mixing or directly layering either AHAs with BHAs with retinol or vitamin C products at the same time of day, in case it causes skin sensitivities.

Instead, the recommendation when using more than one of these ingredients is for staggered application, e.g. using your chemical exfoliant and retinol on alternate nights. If using an AHA/BHA and vitamin C in the same regimen, apply the vitamin C in the morning and exfoliant at night time.

Niacinamide can also be used together with AHAs or BHAs—again, provided they aren’t layered consecutively.

So, now you’re across the difference between alpha and beta hydroxy acids, you can move on to using hyaluronic acid & salicylic acid together!