Exfoliation 101: What You Should Know About AHAs And BHAs In Your Skin Care Products

Chemical exfoliation using AHAs and BHAs rose in popularity during the 1990s. As one of the most common cosmetic services, chemical exfoliation is used for issues involving pigmentation, blemishes, and other skin concerns. The idea is this: A chemical like AHA or BHA destroys the epidermis and dermis layer of skin, enabling it to rejuvenate.¹

However, the concept of chemical exfoliation dates back thousands of years to ancient Egypt. Queen Cleopatra was said to bathe in sour milk to improve the look and texture of her skin. Nowadays, we know that sour milk contains lactic acid, one of the naturally-occurring alpha-hydroxy acids.²

Your skin is the largest organ in your body. And it requires constant care.³ AHAs and BHAs are often included as chemical exfoliants in your skincare products. Read here for the info you need to know about AHAs vs BHAs – and how they might work their magic on various skin types.

What Are AHAs And BHAs?

AHAs and BHAs are two classes of naturally-derived chemical exfoliators called hydroxy acids. They are also known as “fruit acids” because the AHAs and BHAs are derived from natural sources such as fruits, milk, sugarcane, and willow bark.

AHAs and BHAs are often found as active ingredients in chemical peels, gels, cleansers, toners, scrubs, and masks. These substances have been shown to help with the appearance of certain skin concerns such as wrinkles, hyperpigmentation, and hydration. These chemical exfoliants work to help remove dead skin and open up clogged pores.^4,5

The Difference Between AHAs And BHAs: AHAs Are Water Soluble, While BHAs Are Oil Soluble

Although AHAs and BHAs are both hydroxy acids, their mechanisms of action differ in a number of ways, including how deeply they penetrate the skin. Neither is more important than the other; they work in different ways and therefore help tackle different needs.⁶

Alpha Hydroxy Acids

AHAs:

• Are found in sugar cane, some citrus, and other plant sources.
• Are water-soluble (hydrophilic) and stay on the skin’s surface. They break the water bonds that attach dead skin cells to healthy skin.
• Are used for skin issues such as breakouts, pigmentation, dry skin, and wrinkles.⁷

Specific AHAs include:

• Glycolic acid
• Lactic acid
• Mandelic acid
• Malic acid
• Tartaric acid
• Citric acid^8,9

Glycolic acid and lactic acid are often used in skincare products. Glycolic acid is derived from sugar cane. It’s used to exfoliate the top layer of dead skin.^10,11

Beta Hydroxy Acids

BHAs:

• Can be found in sweet birch, wintergreen leaves, and willow tree bark.¹²
• Are oil-soluble (lipophilic) and go deeper into the skin pores. This means that they have the ability to penetrate into the oily cells
  of the sebaceous gland and potentially help unclog pores.
• Are good for people with skin that is prone to periodic breakouts, spots, blemishes, and eruptions on the skin.¹³

The only BHA used in cosmetics is salicylic acid, with citric acid sometimes being classified as a BHA.¹⁴ (Although technically there are other BHAs, like carnitine, they are not used for this purpose).¹⁵ Salicylic acid works by inducing exfoliation of the oily areas of the face at the epidermal-dermal interface.^16,17

Other Potential Benefits Of Using AHAs/BHAs: Can They Help With Sun Damage Or Fine Lines And Wrinkles?

Skin concerns are typically due to two processes: Intrinsic factors, such as hormonal changes that occur with age, and extrinsic factors occurring as a result of exposure to ultraviolet radiation or pollution. As a result of these two concurrent processes, as skin ages, it undergoes a variety of changes. These include losing structure and elasticity, as well as atrophying and wrinkling.¹⁸

Skin also regularly loses moisture, which must be added back in.¹⁹

AHAs Are Ideal For Wrinkles and Fine Lines

AHAs are often included as a component of moisturizers and cream products. Due to their acidic nature, AHAs may help lessen the appearance of sun damage and fine lines caused by photoaging of skin.²⁰

AHAs work by dissolving the “glue” that holds together dead skin cells. In higher concentrations, an AHA may be used in a chemical peel to remove dead skin cells and help improve the appearance of wrinkles, and skin texture.²¹

However, if used in high enough concentrations, the acidity of AHAs may also cause skin irritation and sun sensitivity. Always wear sunscreen and cover your face with a wide-brimmed hat when outdoors, especially if you’ve recently had a chemical peel or use products with AHA or BHAs.²²

BHAs Are Ideal For Oily Skin

BHA, in the form of salicylic acid, may prove beneficial for skin breakouts because it dissolves in oil. It’s able to penetrate into skin pores that contain the oil substance sebum. Salicylic acid acts by softening and exfoliating the outer layer of skin. It may also help decrease the amount of sebum produced by the skin. When used in a peel, salicylic acid is generally safe and effective for most people, though you’ll want to check with your dermatologist before adding BHAs to your skincare routine.²³

Chemical Exfoliants Are Classics, But Always Consult Your Doctor Before Using Them

While chemical exfoliants have been used very prominently for ages, chemical peels may cause skin damage or increased sun sensitivity when used in high enough concentrations.²⁴ Because of this potential danger, chemical peels are best performed by a qualified professional. However, you can buy skincare products formulated to contain AHAs and BHAs at concentrations that are both safe and highly effective for daily use.²⁵

From the days of Cleopatra to the modern era, AHAs and BHAs have been used on sun-damaged, wrinkled and oily, or blemished skin. With modern techniques, products incorporating these chemical exfoliators can be a safe and effective way to make skin appear more youthful.

As with any chemical treatment, whatever your skin goals, always consult with your doctor before making a decision on what to use on your skin.

Learn More:

Sources
1. https://jamanetwork.com/journals/jamadermatology/article-abstract/2657249
2. https://jamanetwork.com/journals/jamadermatology/article-abstract/2657249
3. https://www.nationalgeographic.com/science/health-and-human-body/human-body/skin/
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3941867/
5. https://punicamakeup.com/cosmetics-dictionary/far-know-aha-bha-beneficial-skincare/
6. https://www.byrdie.com/aha-vs-bha
7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6122508/
8. https://cosmeticsinfo.org/alpha-hydroxy-acids
9. https://www.huffpost.com/entry/skin-care-acid-guide_l_5c8ab90ee4b0d7f6b0f10df1
10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6122508/
11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6017965/
12. https://onlinelibrary.wiley.com/doi/full/10.1111/ajd.12715
13. https://www.huffpost.com/entry/heres-exactly-what-salicylic-acid-does-to-your-skin_b_578cff25e4b07cc1115aa329
14. https://www.fda.gov/cosmetics/cosmetic-ingredients/beta-hydroxy-acids
15. https://foodb.ca/compounds/FDB000572
16. https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1529-8019.2000.00018.x
17. https://onlinelibrary.wiley.com/doi/full/10.1111/ajd.12715
18. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3583886/
19. https://my.clevelandclinic.org/health/articles/10980-understanding-the-ingredients-in-skin-care-products
20. https://pubmed.ncbi.nlm.nih.gov/11702315/
21. https://www.dovepress.com/an-antiaging-skin-care-system-containing-alpha-hydroxy-acids-and-vitam-peer-reviewed-article-CCID
22. https://my.clevelandclinic.org/health/articles/10980-understanding-the-ingredients-in-skin-care-products
23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4554394/
24. https://abcnews.go.com/Lifestyle/experts-warn-dangers-home-chemical-peels/story?id=44552377
25. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-labeling-cosmetics-containing-alpha-hydroxy-acids