Updated: March 2026
Salicylic acid and AHAs are two of the most commonly used exfoliating acids in modern skincare. While they work in similar ways, they affect the skin differently and are often recommended for different skin concerns.
This guide takes a closer look at how AHAs and BHAs differ, how each type works, and which may be better suited for concerns like acne, clogged pores, dullness, or uneven skin tone.
Jump to Section
- What AHAs Are
- What BHAs Are
- Key Differences
- Which Is Better for Acne
- Which Is Better for Sensitive Skin
What AHAs Are
AHAs, or alpha hydroxy acids, are a group of exfoliating acids that work mainly on the surface of the skin. They help loosen the bonds between older skin cells, allowing them to shed more easily.
Common AHAs used in skincare include:
- Glycolic acid
- Lactic acid
- Mandelic acid
Because AHAs mainly work on the surface of the skin, they are often used to improve concerns such as dull skin, uneven texture, and mild discoloration.
What BHAs Are
BHAs, or beta hydroxy acids, are another type of exfoliating acid used in skincare. The most well-known BHA is salicylic acid.
Unlike AHAs, salicylic acid is oil-soluble, which allows it to work inside oil-filled pores. Because of this, it is often used for concerns such as clogged pores, blackheads, and acne.
By helping dissolve buildup inside pores, salicylic acid can help reduce congestion and support clearer-looking skin.
A deeper explanation of how salicylic acid works in the skin is covered in our guide Salicylic Acid for Skin.
Key Differences
Although both AHAs and BHAs exfoliate the skin, they work differently.
AHAs
- Work mainly on the skin’s surface
- Help improve skin texture and brightness
- Often used for uneven tone or dull skin
BHAs (Salicylic Acid)
- Can work inside pores
- Help dissolve buildup that contributes to blackheads and acne
- Often used for oily or acne-prone skin
Because of these differences, each type of acid is usually chosen based on the skin concern being treated.
Which Is Better for Acne
For acne-prone skin, BHAs such as salicylic acid are often preferred.
Because salicylic acid can work inside pores, it helps dissolve the buildup of oil and dead skin cells that contributes to clogged pores and breakouts. This makes it particularly useful for concerns like blackheads and mild acne.
AHAs can still support acne routines by helping improve surface texture and preventing dead skin cells from accumulating on the skin’s surface.
Which Is Better for Sensitive Skin
The best exfoliating acid for sensitive skin often depends on how the skin responds and the type of formula being used.
Some people with sensitive skin find gentler AHAs, such as lactic acid or mandelic acid, easier to tolerate. Others may do well with lower concentrations of salicylic acid.
When introducing any exfoliating acid, starting slowly and paying attention to how the skin responds can help reduce irritation.
The Bottom Line
AHAs and BHAs are both exfoliating acids, but they work in different ways.
AHAs primarily exfoliate the surface of the skin and are often used for concerns like dullness or uneven texture. BHAs, such as salicylic acid, can work inside pores and are often used for concerns like blackheads, clogged pores, and acne.
Choosing between them usually depends on the skin concern and the formula being used.
