AHA vs. BHA: Differences, Benefits, Uses and Alternatives

• Hydroxy acids AHA and BHA are two types of chemical exfoliants that can be found in a wide range of over-the-counter skin care products such as cleansers, toners, serums, moisturizers, peels and masks
• Although they do share similarities, AHAs primarily target surface concerns while BHAs penetrate deeper to treat more serious skin issues
• Both types can be used simultaneously depending on your goals, however one type will be more appropriate for your skin type and concern than the other   

Chemical exfoliants play a key role in an effective skin care routine and in the management of inflammatory skin conditions such as rosacea and acne; they do so primarily by clearing the outermost layer of skin of debris and dead skin cells, and by reducing inflammation. Alpha hydroxy acids (AHA) and beta hydroxy acids (BHAs) are two types of exfoliants that can achieve these results; whether you choose AHA vs. BHA will depend on your skin type and skin condition.

What Are AHAs and BHAs?

AHAs and BHAs are both highly effective chemical exfoliants – acids that slough off dead skin cells and debris, and speed up skin cell turnover for improved texture. They work by breaking the bonds that hold dead skin cells together which can block pores and dull the complexion. 

Both types of acids have also been demonstrated to prevent, manage and treat several inflammatory skin conditions including acne and rosacea. Specifically, they have been demonstrated to decrease skin cell buildup, promote wound healing, break up and disperse  hyperpigmented patches and increase collagen production.  

As well, both types have been shown to exhibit antioxidant activity, with BHAs having stronger effects. Antioxidants play a key role in protecting skin by neutralizing free radicals which can damage skin. 

Both types of exfoliants have antimicrobial and antibacterial qualities to kill acne-causing bacteria and reduce redness and inflammation, making them ideal as a treatment and preventative for some inflammatory skin disorders. 

All skin types can benefit from a chemical exfoliant as they brighten and smooth the complexion; as well, having clear pores allows for better penetration of any skin care products you apply afterward. 

What Are the Differences Between AHAs and BHAs?

AHAs are water-soluble and work on the skin’s surface to exfoliate dead skin cells; BHAs are oil-soluble which enables them to penetrate the skin via sebaceous (oil) glands to clear excess sebum and remove dead skin cells. While both types exfoliate, they perform differently.

AHAs are gentler than BHAs as they remain surface level. They can support the skin’s natural cell turnover process and treat minor pigmentation concerns such as redness that remains from healed acne lesions and mild hyperpigmentation. Their mild effects means skin is less likely to be irritated.

BHAs are more intensive, as they penetrate the skin to not only target dead skin cells, but excess oils and damaged hyperpigmented cells. 

This solubility is what differentiates AHAs from BHAs. 

Benefits of AHAs vs. BHAs

When used regularly as part of an effective skin care regimen, both types can exfoliate skin to reveal a brighter, more even complexion. Which type you choose will depend on your particular needs and goals.   

AHAs 

In addition to exfoliation, AHAs are prized for their skin-refining and antiaging benefits: 

• Smoothes and refines dull skin and improves skin texture
• Plumps and firms skin by promoting collagen synthesis
• Attracts and retains moisture for deep hydration by increasing hyaluronic acid levels
• Softens the look of fine lines and wrinkles
• Minimizes the appearance of atrophic acne scars
• Lightens sunspots, liver spots and age spots caused by overexposure to the sun
• Fades postinflammatory hyperpigmentation (PIH) caused by healed acne blemishes
• Alleviates inflammatory skin conditions such as acne due to its antimicrobial properties; inhibits melanin production to help treat melasma

Glycolic acid and lactic acid are two of the most popular hydroxy acids within the AHA family. 

BHAs

BHAs can achieve all of the above benefits but with greater efficacy due to their oil-solubility; this enables deeper penetration to effectively treat more severe skin concerns. As well, they can provide additional benefits including the following: 

• Antibacterial characteristics tamp down inflammation and help control symptoms of acne and rosacea, including redness
• Treats noninflammatory acne by clearing pores of blackheads and whiteheads and sloughing off dead skin cells
• Penetrates follicles to decrease oil production to control oily skin 
• Targets the effects of sun damage including fine lines and wrinkles, and hyperpigmented dark spots to restore smoothness and even tone

As AHAs are more gentle than BHAs, they address surface-level concerns such as mild hyperpigmentation or slight oiliness, in addition to dry skin. Oil-soluble BHAs penetrate skin to address deeper skin concerns such as acne, buildup of dead skin cells and excess sebum. 

Salicylic acid is the most popular BHA and is an established treatment for inflammatory skin disorders such as acne and psoriasis.

Is one better than the other?

Neither AHAs or BHAs are superior to the other, and your choice of exfoliant will depend largely on your skin type and any concerns you wish to address. 

Should I Use an AHA or BHA?

When choosing an AHA or BHA, consider your skin type; AHAs are gentle and therefore best-suited for dry or normal skin types; because BHAs are more aggressive they would be more suitable for oily or combination skin. Lower concentrations can also be appropriate for sensitive or inflamed skin. 

You also need to identify your goals. For example, if  you are looking to manage acne breakouts, then BHA would be the optimal choice due to its antibacterial effects; AHAs would be the best choice for PIH or as an anti-aging solution. 

How often you use your hydroxy acid product will depend on your skin type and how it reacts; some people can use it every day, others no more than twice a week. To avoid damaging your skin barrier, monitor your skin for redness and irritation. 

AHA candidates

AHA is appropriate for all skin types to clear pores of debris, dead skin cells and grime; smooth fine lines and wrinkles; boost collagen; improve texture and tone and produce an overall rejuvenated appearance.

One important point to consider is the type and concentration of your selected AHA; when used in low concentrations skin can be enhanced; in high concentrations, such as in a professional chemical peel, swelling, burning, and itching can occur. 

AHAs can make your skin more sensitive to the sun and increase your risk of sunburn. Apply an SPF of at least 30 to protect your skin from damage.

Types of AHA	Skin Types	Skin Condition/Concern
Citric acid	All types especially oily; not sensitive	Improves skin texture; unclogs pores; evens tone
Glycolic acid	Normal, combination, oily	Acne; promotes skin cell turnover, strong ability to stimulate collagen production; boosts moisture, lightens dark spots
Lactic acid	All types, especially dry, sensitive, mature skin	Rosacea; sloughs off dead skin cells; reduces lines and wrinkles; lightens dark spots
Malic acid	Normal, oily, dry	Promotes skin cell turnover; smooths and evens skin tone
Mandelic acid	Normal, oily	Acne, rosacea; smooths skin, unclogs pores; targets dullness
Tartaric acid	All types	Acne; sun damage; softens lines and wrinkles, shrinks large pores; lightens dark spots; evens skin tone

BHA Candidates

As with AHAs, how often you use BHAs will depend on your skin type and tolerance. Although BHAs don’t increase the risk of skin sensitivity to the sun, you should always apply sunscreen every day to protect your skin from sun damage.

BHAs are best for oily or acne prone skin as they control sebum production and can clear pores of acne-causing debris.

Types of BHA	Skin Types	Skin Condition/Concern
Citric acid	All types except sensitive; best for oily skin	Oiliness; clogged pores; ,hyperpigmentation
Salicylic acid	Acne-prone, oily, mature	Calms inflammation and redness; breaks down comedones, sloughs off dead skin cells; smooths fine lines

Can you combine AHAs and BHAs?

Yes, you can use an AHA and BHA together to garner the most benefits for your skin. However, do so with caution as your skin barrier can become unbalanced and skin can become irritated, uncomfortable and inflamed. 

For best results start with a BHA product to deeply cleanse skin and follow with an AHA to clear any surface debris and residue. For example, you can use a  salicylic acid face wash to clear oily skin and follow with a glycolic acid toner.  

You can also use a BHA product in the morning and an AHA at night, which enables a routine that is flexible and can be adjusted depending on how your skin reacts.

Lastly, you can find products that contain both hydroxy acids in balanced concentrations that take the guesswork out of your skin care routine.

Alternatives to AHA and BHA

Both AHAs and BHAs can be too harsh for sensitive or very dry skin, and can cause irritation in the form of redness, stinging and peeling. Some people may have an allergic reaction.

If hydroxy acids are not suitable for you, there are a number of effective alternatives available.

Lipohydroxy acids

Lipohydroxy acids (LHAs) are derived from salicylic acid and offer the same superior exfoliating benefits. They break apart the bonds that hold dead skin cells together to reveal skin that is clear and smooth.

As with salicylic acid, LHAs can break up and dissolve comedones, and boost collagen and elastin levels to plump and smooth skin.

Its unique composition renders it more tolerable than salicylic acid, making it ideal to treat dry and sensitive skin; unlike salicylic acid, LHAs are oil-soluble, making them an excellent choice for acne-prone skin

This acid has been proven to be as effective as benzoyl peroxide, a first-line therapy for acne but without the associated side effects.

Polyhydroxy acids

Polyhydroxy acids (PHAs) are another hydroxy acid that provides similar effects as glycolic and salicylic acid but with less irritation; they also have antioxidant qualities to protect skin from damage.

These acids fall under the humectant class, attracting and retaining moisture to add fullness to skin and protecting the moisture barrier. All skin types would benefit from this acid due to its gentle nature, especially dry or sensitive skin and those with eczema or rosacea.

Retinol

Retinol has been shown to provide significant anti-aging effects. 

Derived from vitamin A, retinol is a well-known ingredient that is prized for its anti-aging effects.

While not an exfoliant, it penetrates the top layer of skin to increase skin cell proliferation, boost collagen and elastin in skin, and generate a plumping effect to smooth fine lines and wrinkles.

Retinol is appropriate for all skin types but can cause redness, peeling and irritation at first use. Choose a lower concentration when you  first add it to your skin care routine and use just 1–2 times per week until your skin becomes accustomed to it.

Takeaway

AHAs and BHAs are both effective chemical exfoliants and both offer a number of important  benefits for all skin types. They can lift away dulling dead skin cells and excess oils, lighten hyperpigmentation, even tone, promote collagen production, moisturize and soften the appearance of lines and wrinkles. 

The primary difference between the two is that AHAs are water-soluble and have an effect on the top layer of skin only; BHAs are oil-soluble and can therefore penetrate follicles to achieve more dramatic effects at a deeper level.

Depending on your skin type and concerns, one type will be more suitable than the other. However, you can also take advantage of what each has to offer by combining both in your skin care regimen. 

If you are sensitive to hydroxy acids, there are a number of effective alternatives suited to different skin types and conditions which help to clear pores of dead skin cells and debris, and slough off dead skin cells.