AHAs and BHA: Differences Between Them and How to Choose the Best Exfoliant
Our skin naturally exfoliates dead cells every day, but over time—primarily as a result of age and unprotected sun exposure—this shedding process slows and may stop altogether. This results in dull, dry, or flaky skin; clogged, enlarged pores; bumps, wrinkles, loss of firmness, and uneven skin tone.
Helping skin gently exfoliate its buildup of dead skin—the way it naturally did when we were younger—reveals the beautiful, soft, hydrated skin hiding beneath, as quickly as overnight. Without question, a leave-on AHA (alpha hydroxy acid) or BHA (beta hydroxy acid) chemical exfoliant can make a world of difference in your skin’s appearance. We’re often asked which one is best, and the answer is less complicated than you might think.
How AHAs and BHA are Similar
AHAs (alpha hydroxy acids, e.g. glycolic and lactic acids) and BHA (beta hydroxy/salicylic acid) both act to “unglue” the bonds holding dull, dead skin on the surface. Once those bonds are broken—gently and evenly—skin naturally sheds its spent cells. So, although you won’t actually see your skin exfoliating, you’ll soon see (and feel) the smoother, younger-looking skin.
To work effectively, AHA and BHA exfoliants must be formulated within a narrow pH range, between 3 and 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.
Additionally, AHA and BHA both:
- diminish the look of lines and wrinkles
- make skin look and feel firmer
- hydrate skin
- improve the look of dull, uneven skin tone
- smooth rough, bumpy texture
But each also has unique properties making them preferable for certain skin types and concerns.
How AHAs and BHA are Different
AHAs are water soluble so only work on skin’s surface. They are generally preferred for normal to dry, sun-damaged skin, due to their ability to enhance natural moisturising factors within skin (as mentioned above, BHA is also hydrating, but it hydrates skin in a different way than AHAs do). AHAs have also been proven effective in reducing the visible signs of sun damage, including crepe-y skin and wrinkles.
BHA works on skin’s surface and deep inside the pore; it’s oil soluble, so it’s most often preferred for normal to oily skin prone to bumps, clogs, blemishes, and enlarged pores. BHA also has natural skin-calming properties, so it’s gentle enough for skin that's sensitive or prone to redness or rosacea. This well-rounded, gentle ingredient is even suitable for bumpy skin disposed to milia.
Can You Combine AHA and BHA?
With so many shared and unique benefits, we’re routinely asked, “Should I use both an AHA and BHA product to get the best results?” In short, no, but it’s up to you; all Paula’s Choice AHA and BHA exfoliants are formulated to work brilliantly on their own and will provide remarkable results for various skin types and concerns.
On the other hand, there’s nothing wrong with using both or experimenting to see which one works best for you by either (1) applying them at the same time, either morning or evening, or (2) alternating their use. Using an AHA exfoliant and BHA exfoliant at the same time (both provide what’s known as chemical exfoliation, rather than the “mechanical” action of a scrub) is not as complicated or scary as it might seem. If you’re choosing well-formulated, gentle exfoliants, there really isn’t a downside—you just have to monitor how your skin responds and adjust usage if needed.
You don’t need to use both an AHA and BHA exfoliant at the same time out of fear that you’re “missing out” because one is more anti-ageing than the other. In truth, both provide anti-ageing benefits; they just do so differently. The reason for using an AHA and BHA exfoliant at the same time is really about whether or not your skin needs more thorough exfoliation. This might be the case for those who have advanced signs of sun damage, deep wrinkles, stubborn clogged pores and bumps, or dull, flaky skin.
How to Use Both AHA and BHA In Your Skin Care Routine
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 but experiment to see which combination and frequency of application work best for you. (See what we mean about the need to experiment?)
As for how to use both at the same time—apply the exfoliants after cleansing and toning, starting with whichever has the thinnest texture; for example, you’d apply a liquid texture before a gel or lotion. You don't need to wait for one to absorb before applying the next, and you can immediately follow with the rest of your skin care routine--it won’t throw off the pH of either exfoliant.
Alternating between AHA and BHA products to exfoliate your face might seem too complicated, but it doesn’t have to be that way. It’s fine to alternate, and it can be a great way for all skin types to experience the distinct benefits of each. In fact, many people find that alternating AHA and BHA exfoliants is the perfect solution to address their unique concerns.
Here are tips on how to alternate exfoliants and how often 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.
- Once or twice per week, rotate into your routine a higher-strength specialty AHA or BHA treatment to give yourself an “at-home peel” experience that delivers more dramatic results.
Ultimately, there’s no single best way to go about using AHA and BHA exfoliants; it’s all about experimentation to find what works best for you and then adjusting as needed based on the changing needs of your skin. What counts is that you keep using a leave-on chemical exfoliant--and we suspect you’ll willingly do that once you see how routine use remarkably transforms your skin (get ready for compliments)!
References for this information:
Clinical, Cosmetic, and Investigational Dermatology, August 2015, pages 455–461
Dermatology Research and Practice, February 2015, ePublication
Journal of the German Society of Dermatology, July 2012, pages 488–491
Evidence Based Complementary and Alternative Medicine, June 2011, ePublication
Clinical, Cosmetic, and Investigational Dermatology, November 2010, pages 135–142
Journal of the American Academy of Dermatology, April 2007, pages 651–663
About the Experts
Paula Begoun is the best-selling author of 20 books about skincare and makeup. She is known worldwide as The Cosmetics Cop and creator of Paula’s Choice Skincare. Paula’s expertise has led to hundreds of appearances on national and international radio, print, and television including:
The Paula's Choice Research Team is dedicated to busting beauty myths and providing expert advice that solves your skincare frustrations so you can have the best skin of your life!