Understand the Differences Between AHA, BHA, and PHA: 3 Types of Skincare Exfoliants

Exfoliation is an important approach in skincare that can help remove accumulated dead skin cells and improve the appearance and texture of the skin. In addition to physical exfoliation, the cosmetic industry widely uses chemical exfoliants, particularly ingredients belonging to the hydroxy acid family.

Among the most commonly recognized terms are AHA (Alpha Hydroxy Acid), BHA (Beta Hydroxy Acid), and PHA (Polyhydroxy Acid). Although all three are associated with exfoliating skincare products, their characteristics, applications, and tolerability can differ.

Understanding these differences is important not only for consumers choosing skincare products but also for formulators and brands selecting active ingredients according to a product's intended positioning and formulation objectives.

Table of Content:

• What Is AHA?
• What Is BHA?
• What Is PHA?
• Which One Is Right for Your Skin?
• From Ingredient Selection to Formulation

What Is AHA?

Alpha Hydroxy Acids (AHAs) are hydroxy acids widely used in cosmetic and dermatological products. Common examples include glycolic acid and lactic acid, while citric acid may also be used in certain formulations.

AHAs are commonly incorporated into products designed to improve the appearance of skin texture and tone, fine lines, and overall skin condition. Glycolic acid, in particular, has been extensively used in anti-aging formulations, moisturizers, chemical peels, and products intended to improve the appearance of hyperpigmentation and acne.

Read Also:
AHAs in Skincare Products: Why Do Their Levels Need to Be Tested?

AHA may be considered for:

• Uneven skin texture
• Dull-looking skin
• The appearance of fine lines
• Hyperpigmentation and uneven skin tone
• Users seeking surface exfoliation

Proper use is essential. The U.S. FDA notes that topical AHA use may increase skin sensitivity to ultraviolet radiation during use. Therefore, sunscreen, protective clothing, and appropriate sun protection are important when using AHA-containing products.

What Is BHA?

In skincare terminology, BHA (Beta Hydroxy Acid) commonly refers to salicylic acid. The FDA notes that salicylic acid is not technically a true BHA from a chemist's perspective, although the terminology has become widely established within the cosmetics industry and among consumers.

Salicylic acid is frequently found in products developed for oily and acne-prone skin. The American Academy of Dermatology also includes topical salicylic acid among the recommended topical therapies in its acne clinical guidelines.

BHA may be considered for:

• Oily skin
• Acne-prone skin
• The appearance of clogged pores
• Blackheads and whiteheads
• Exfoliating products focused on blemish-prone skin

As with other exfoliating acids, skin tolerance should always be considered. The FDA recommends following product directions, testing BHA-containing products on a small area first, discontinuing use if persistent irritation occurs, and using appropriate sun protection.

What Is PHA?

Polyhydroxy Acids (PHAs) are a relatively newer class of hydroxy acids in cosmetic applications. Examples include gluconolactone, while closely related bionic acids include ingredients such as lactobionic acid.

PHAs have been explored as alternatives capable of delivering several hydroxy-acid-related benefits with potentially improved tolerability. Dermatological literature has also described polyhydroxy and bionic acids as providing additional benefits associated with moisturization, skin-barrier support, and antioxidant/chelating properties.

These characteristics make PHAs particularly interesting for formulations designed around gentle exfoliation.

PHA may be considered for:

• Sensitive skin
• First-time chemical exfoliant users
• Skin requiring gentler exfoliation
• Skin-barrier-focused formulations
• Users with lower tolerance to more intensive exfoliating acids

Which One Is Right for Your Skin?

There is no single hydroxy acid that is automatically the best choice for everyone. AHA may be considered when the primary goal is improving the appearance of uneven texture, dullness, fine lines, and uneven skin tone.

BHA, particularly salicylic acid, is commonly incorporated into formulations targeting oily and acne-prone skin. Meanwhile, PHA can provide an alternative when gentler exfoliation is desired, particularly in formulations intended for sensitive skin or users with lower tolerance to exfoliating acids.

Selecting an active ingredient should therefore go beyond skincare trends. During cosmetic product development, factors such as ingredient type, concentration, formulation pH, ingredient compatibility, stability, safety, and intended product claims should be evaluated comprehensively.

From Ingredient Selection to Formulation

Choosing between AHA, BHA, and PHA is only one part of skincare product development. Product performance does not depend solely on the presence of a trending active ingredient.

Raw-material quality and how an ingredient is incorporated into the formulation system also play an important role in achieving the desired product performance, stability, and characteristics. Understanding the properties of each ingredient is therefore an essential step in transforming a skincare concept into a well-designed formulation.

Developing a skincare product featuring AHA, BHA, PHA, or Other functional ingredients?

Explore ingredient options and raw-material solutions tailored to your formulation needs with IML Testing and Research. Consult with our team to identify suitable ingredients for your product concept and formulation objectives.

Author & Editor: Lina

References

U.S. Food and Drug Administration (FDA). Alpha Hydroxy Acids. Informasi mengenai penggunaan AHA dalam kosmetik, keamanan, sensitivitas terhadap UV, serta rekomendasi penggunaan perlindungan terhadap sinar matahari.

U.S. Food and Drug Administration (FDA). Guidance for Industry: Labeling for Cosmetics Containing Alpha Hydroxy Acids. January 2005.

U.S. Food and Drug Administration (FDA). Beta Hydroxy Acids. Informasi keamanan dan penggunaan BHA/salicylic acid dalam produk kosmetik.

Green, B. A., Yu, R. J., & Van Scott, E. J. (2009). Clinical and cosmeceutical uses of hydroxyacids. Clinics in Dermatology, 27(5), 495–501. https://doi.org/10.1016/j.clindermatol.2009.06.023

Kornhauser, A., Coelho, S. G., & Hearing, V. J. (2010). Applications of hydroxy acids: classification, mechanisms, and photoactivity. Clinical, Cosmetic and Investigational Dermatology, 3, 135–142.

American Academy of Dermatology (AAD). Acne Clinical Guideline. Clinical recommendations for acne management, including topical salicylic acid.