The Difference Between AHA and BHA Exfoliants

In this article:
What are AHAs?
What are BHAs?
Are AHA and BHA good for skin?
Why are AHAs and BHA different?
Can you use AHA and BHA together?
How to use AHAs and BHAs
Can AHA and BHA damage skin?

Our skin naturally exfoliates dead cells every day, but over time—primarily because of age and unprotected sun exposure—this shedding process slows and may stop altogether (1). The undesirable results of this slow down include dull, dry or flaky skin; clogged, enlarged pores; bumps, wrinkles, loss of firmness and uneven skin texture.

Without question, a leave-on AHA (alpha hydroxy acid) or BHA (beta hydroxy acid) chemical exfoliant can make a world of difference with these concerns, helping to remove the buildup of dead skin and reveal the healthier, smoother complexion hiding beneath.

Use this guide to determine which chemical exfoliant option is best for your skin type and skin concerns for glowing, healthy skin.

What are AHAs?

AHAs are a class of ingredients that help exfoliate skin’s upper layers. They can be naturally derived from sources like plants or milk, though most AHAs used in skin care products are lab created for greater stability.

There are several different types of AHAs, among them lactic, glycolic and mandelic acids. Some of the benefits you’ll see from using AHAs include (2):

• Increased skin hydration
• A reduction in the visible signs of sun damage, including fine lines, wrinkles and loss of skin elasticity
• Improved appearance of dark spots and uneven tone
• Enhanced effects of other skin care products due to the sloughing of dead skin cells

What are BHAs?

BHA shares some similarities with AHAs, but the two also have distinct differences. There's one main BHA, salicylic acid. Like AHAs, BHA exfoliates skin’s surface – but much of its benefits derive from its ability to exfoliate deep into pores thanks to its oil-soluble nature (3). These are some of the improvements you’ll see if you begin using BHA on a regular basis:

• A decrease in the amount of visibly clogged pores
• Fewer occurrences of blackheads
• The look and feel of less reddened, sensitised skin
• Less oily skin, since BHA can thin oil that’s become too thick

Are AHA and BHA good for skin?

AHA and BHA are good for skin thanks to the way they exfoliate in a non-abrasive manner by “ungluing” the bonds holding dull, dead skin on the surface. Once those bonds are broken—gently and evenly—skin sheds its spent cells. This action mimics the way skin cells naturally slough off when we’re younger.

Exfoliation helps strengthen and restore balance to skin’s barrier, our defence against environmental assault (4). The more you can do to replicate skin’s pre-damage state, the healthier skin you’ll have!

We’ve said it before and we’ll mention it again here as well: for AHAs and BHAs to work their best, they must be well-formulated, meaning they do not contain irritating or harsh ingredients (such as fragrance or denatured alcohol) and be at a pH between 3-4, which is where they work at optimal effectiveness.

Why are AHAs and BHA different?

We touched on some of the differences between AHAs and BHAs a little earlier, but here’s a more detailed guide to what makes them distinct from each other.

AHAs are water soluble, which means they exfoliate on the surface and top layers of skin. They are generally preferred for normal to dry, sun-damaged skin due to their ability to enhance natural moisturising factors within skin. AHAs have also been proven effective in reducing the visible signs of sun damage, including crepey skin and wrinkles.

BHA is oil soluble, so it not only works on skin’s surface but also deep inside the pore, making it the preferred option for normal to oily skin prone to bumps, clogs, blemishes and enlarged pores. BHA also has natural skin-calming properties, allowing it to be gentle enough for skin that's sensitive or prone to redness. It’s even suitable for those struggling with rosacea. This well-rounded ingredient is also even suitable for bumpy skin disposed to milia and keratosis pilaris (5).

Can you use AHA and BHA together?

Yes, you can use AHA and BHA together. While most people do just fine picking one or the other, there’s nothing wrong with using both or experimenting to see which one works best for you. Just monitor how your skin responds and adjust usage if needed.

Do you need to use both AHA and BHA in your skin care routine? The answer is no. Using either one will provide impressive results that you’ll see both immediately and over time. That being said, using AHA and BHA together can provide advanced results if you’re experiencing multiple skin concerns (such as signs of sun damage, deep wrinkles, stubborn clogged pores, bumps and dull, flaky skin). In fact, many people find that alternating AHA and BHA exfoliants is the perfect solution to address their unique concerns.

How to use AHAs and BHAs

You can use both AHA and BHA in your routine by alternating application (e.g. using AHA one day, BHA the next) or by selecting a formula that gently blends them together. Should you apply an AHA and BHA exfoliant at the same time twice per day? Probably not. Most people don’t need that level of exfoliation.

Apply your AHA/BHA exfoliant after your cleanser and toner steps. You don’t need to wait before moving on to your next product—you can immediately follow with the rest of your routine (it won’t throw off the pH of the exfoliant).

Exfoliation tips and how to exfoliate:

• Most people do fine exfoliating once daily, morning or evening based on personal preference.
• If you want to alternate an AHA and BHA, simply decide which exfoliant to use at the beginning of each week and then switch back and forth day by day. You can also use one for a week, then switch to the other the next week.
• Another option is to apply one type of exfoliant in the morning and the other at night. This can be a great approach for breakout-prone skin showing signs of sun damage.
• You also can experiment by alternating different strengths of an AHA or BHA—or both! For example, apply a 1% BHA exfoliant each morning and step up to a 2% strength at night. You can even experiment with using products that combine different AHAs, like our 6% Mandelic Acid + 2% Lactic Acid Liquid Exfoliant.
• Once or twice per week, you can add a higher-strength specialty AHA or BHA treatment to give yourself an “at-home peel” experience that delivers more dramatic results. If you opt to do this, skip using your regular leave-on exfoliant.

For daytime, always finish with broad-spectrum sunscreen. Other than that, it’s all about experimentation to find what works best for you. What counts is that you keep using a leave-on chemical exfoliant consistently to maintain the results.

Can AHA and BHA damage skin?

AHA and BHA exfoliants do not damage skin when well-formulated and used properly. In fact, AHAs strengthen skin by supporting healthy collagen and BHA delivers soothing properties to calm agitated skin (6, 7).

For best results, AHA and BHA exfoliants need to be formulated within a pH range between 3-4. Paula’s Choice Skincare is aware of the research around this issue, so all of our AHA and BHA exfoliants are formulated to be as effective, and as gentle, as possible. As with every Paula’s Choice product, our chemical exfoliants are fragrance-free plus each contains unique blends of skin-soothing ingredients.

Learn more about exfoliants.

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References for this information:
1. Plastic and Reconstructive Surgery – Global, December 2016, pages 1–6
2. Journal of the German Society of Dermatology, July 2012, pages 488–491
3. Clinical, Cosmetic, and Investigational Dermatology, August 2015, pages 455–461
4. Cosmetic Dermatology: Products and Procedures, Second Edition, 2016, pages 346-356
5. Dermatology Research and Practice, February 2015, pages 1–5
6. Journal of Cosmetic Dermatology, April 2004, pages 76-87
7. Experimental Dermatology, July 2019, pages 786-794