Exfoliation Basics: Alpha Hydroxy Acid (AHA) vs. Beta Hydroxy Acid (BHA)

Written by Jennifer Gordon, MD, Board Certified Dermatologist on November 16, 2020 One Comment

AHA vs BHA compare

Exfoliation is the process of removing dead skin cells and other unwanted debris that cling to the epidermis (the outer layer of the skin). Regular exfoliation of both the face and the body is an important part of maintaining healthy skin that looks and feels great. Consistent exfoliation removes buildup of old skin cells and debris to reveal youthful, hydrated and softer skin. Proper exfoliation also helps maintain proper skin cell turnover rates, a key process to youthful and healthy skin that naturally slows overtime due to aging and sun exposure.

There are two primary ways to undertake at-home exfoliation: chemical exfoliation and mechanical exfoliation. Chemical exfoliation uses topical formulations containing ingredients and enzymes like hydroxy acids to remove the outer layer of the skin. Hydroxy acids come in a variety of products such as face masks, cleansers and scrubs, peels, toners, and moisturizers.

There are two main types of hydroxy acids: Alpha Hydroxy Acid (AHA) and Beta hydroxy acid (BHA). While they sound similar, AHA and BHA are actually very different. Keep reading this post to learn more about hydroxy acid and determine which exfoliation option is best for your individual needs.

Alpha Hydroxy Acids (AHA)

What AHAs Are Made From: 

Alpha Hydroxy Acids, or AHAs, are extracted from natural sources such as sugar cane and other plants. Also known as fruit acids, they are commonly found in grapes, apples and citrus.

What AHAs Do: 

AHAs are most commonly used to exfoliate the outer layer of the skin, the epidermis. Exfoliation with AHAs evens skin tone and promotes a smoother, more youthful appearance.

Shedding old skin cells promotes collagen production, making AHAs ideal for those seeking to eliminate fine lines and wrinkles.

  • Evens skin tone and reduces visible signs of sun damage
  • Smooths fine lines and crepey skin to reduce signs of aging
  • Increases moisturization of the epidermis

The Best Skin Type for AHAs:

AHAs are water soluble, so they work best on the skin’s surface, versus deep down where they’d need to mix with the skin’s oils. Because of this, they’re great for sensitive skin types or for those with normal to dry, not oily, skin. AHAs may help moisturize dry skin by stimulating the production of oils via exfoliation.

Types of AHAs:

  • Glycolic Acid
  • Citric Acid
  • Lactic Acid
  • Malic Acid

Beta Hydroxy Acids (BHA)

What BHAs Are Made From: 

Beta Hydroxy Acids, or BHAs, are extracted from plants such as willow bark or birch trees. The organic carboxylic acids can also be chemically synthesized.

What BHAs Do: 

Because BHAs are oil-based they are able to mix with skin’s natural oils to target deeper layers of the skin and the insides of pores. BHAs are frequently used by those seeking to reduce acne, clear pores and reduce the appearance of enlarged pores.

BHAs have some of the same general exfoliating properties of AHAs and are also effective in reducing sun damage and evening skin tone.

  • Evens skin tone and reduces visible signs of sun damage
  • Breaks up sebum and dead skin cells in clogged pores
  • Reduces the appearance of enlarged pores and acne scars

The Best Skin Type for BHAs:

BHAs are fat soluble and thus work best with oily skin types. They are generally gentler than AHAs, making them ideal for those with skin that’s sensitive to over-drying or irritation. Low concentration BHAs help reduce redness or rosacea for those who are seeking to even their skin tone.

Types of BHAs:

  • Salicylic Acid
  • Tropic Acid
  • Trethocanic Acid
  • BHA Citric Acid

How to Use AHAs and BHAs

Depending on the product, you can use AHAs or BHAs in the morning or at night. Higher concentrations are sometimes meant to be worn overnight for greatest exfoliation, while lower concentrations can safely be applied in the morning, or both day and night.


Because AHAs offer significant exfoliation, it’s best to use these products every other day until you’re sure your skin won’t become over dried or irritated. Remember that AHAs make your skin more sensitive to the sun, so pair with a daily moisturizer that contains sunscreen.


BHAs are gentler and typically safer for daily use. That said, you should still take your time introducing them to your routine. Although they won’t make your skin as sensitive to the sun as AHAs, it can’t hurt to combine BHA use with a daily sunscreen to prevent further sun damage.

Should You Use Both?

To fight acne, wrinkles, and sun damage, there’s no reason not to combine AHAs and BHAs, although you may not want to apply them both twice daily. Both are exfoliants, and when used together they can irritate the skin, cause dryness, or may even cause excessive oil production. When stripped of its natural oils, your skin will try to balance itself by producing more. To reap the benefits of both AHAs and BHAs, try any of the following and see what works best for you.

  • Use BHAs in the morning, and AHAs at night
  • Use just one, in the morning or at night, and alternate daily
  • Use just one, once or twice per day, and alternate weekly
  • Use lower concentrations in the morning, and higher concentrations at night
  • Use a higher concentration peel once per week, alternating types

There’s no right or wrong way to combine AHAs and BHAs. The best course of action is to experiment to see what works best for your skin. Give your skin at least 2-4 weeks to settle into your new routine before deciding if you need to make a change.

Jennifer Gordon, MD

Dr. Gordon is Board Certified by the American Board of Dermatology and is a member of the American Society of Dermatologic Surgery (ASDS), the American Academy of Dermatology, the Dermatology Foundation, the Texas Medical Association and the Travis County Medical Society. Currently, Dr. Gordon oversees our South Austin location.

One Response to “Exfoliation Basics: Alpha Hydroxy Acid (AHA) vs. Beta Hydroxy Acid (BHA)”

  1. Avatar Holley says:

    Great info! I love Skin Medica AHA/BHA cleanser!

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