AHA, BHA, or PHA? Choosing a Chemical Exfoliant

Choose an exfoliant by the concern you want to address: an AHA for surface texture, a salicylic-acid acne treatment for acne, or a PHA toner marketed for gentler exfoliation when you prefer that format. Exfoliation is optional. If your skin is already irritated, peeling, or sunburned, adding an acid is unlikely to be a helpful next step.

“Clean” does not tell you an acid’s strength or how often to use it. The FDA explains that an AHA’s exfoliating effect depends on its type, concentration, pH and surrounding formula. A higher percentage alone does not make a better purchase. FDA: Alpha Hydroxy Acids.

Compare these three specific formulas

The Ordinary Lactic Acid 5% + HA: a surface-focused AHA

This water-based serum discloses 5% lactic acid and a pH range of 3.60–3.80. It is a useful comparison for someone seeking a leave-on surface exfoliant with a disclosed acid level. Its ingredient list includes glycerin and sodium hyaluronate crosspolymer.

There is an important distinction between its marketing and directions: although the overview mentions sensitive skin, the use instructions say not to use it on sensitive, peeling or compromised skin. Follow that warning. The label advises avoiding the eye area, patch testing and stopping if irritation occurs. The Ordinary product page.

A 5% formula is not an automatic beginner pass. If you want treatment for acne rather than surface texture, consider an acne-labeled product instead of expecting this serum to fill both roles.

The Ordinary Salicylic Acid 2% Solution: a BHA acne treatment

The current U.S. product is labeled for acne control. Its instructions start with a thin layer on the affected area, beginning with one application daily because dryness can occur. They advise reducing frequency if bothersome dryness or peeling develops and warn that another topical acne medication can increase irritation. Manufacturer’s U.S. product and directions.

This is the more direct comparison for someone shopping for a salicylic-acid acne treatment. Do not confuse it with the brand’s anhydrous solution or rinse-off products; those are different formulas. Use the exact package directions, including its new-user sensitivity test, rather than applying a generic exfoliation schedule.

The INKEY List PHA Toner: a gentler-positioned leave-on option

This toner discloses 3% gluconolactone, a PHA, and 3% niacinamide. Its water-light format may appeal if you prefer a toner to a dropper serum. The manufacturer markets it for sensitive skin, but that is not a promise of no reaction.

The page’s “How to Use” section advises starting one or two times per week, while its FAQ gives a slightly different starting frequency. Use the more conservative introduction and follow your bottle’s instructions. The brand’s How to Use section also advises against layering it with other exfoliating acids, retinol or vitamin C. INKEY PHA Toner.

Which choice fits your situation?

The AAD cautions that exfoliation can worsen dryness when combined with retinoids or benzoyl peroxide. It also notes that aggressive exfoliation can contribute to dark spots, particularly in darker skin tones. AAD: How to safely exfoliate at home.

Introduce one product, not an acid collection

Begin with one exfoliant and keep the rest of your routine familiar. Follow that product’s contact time and frequency: a leave-on serum should not inherit instructions from a wash-off peel. Avoid the eye area and damaged skin. Persistent burning, a rash or marked peeling is a reason to stop, not proof that the product is “working.”

If prescription treatment or a skin condition complicates the decision, ask your clinician about the exact formula. Strong home peels and mixing your own acids are unnecessary extensions of a basic skincare routine.

For a simple supporting routine, see fragrance-free cleansers and moisturizers.

Follow the AHA sunburn warning

FDA recommends a warning that AHAs may increase sensitivity to sunburn. Use sunscreen, protective clothing and limited sun exposure during use and for one week after stopping. Evening application does not remove this concern. FDA AHA guidance.

Our sunscreen comparison can help with finish and tint. Keep your protection routine consistent rather than reducing the amount of sunscreen to accommodate another skincare layer.

Sources

• FDA: Alpha Hydroxy Acids
• AAD: Safe exfoliation
• The Ordinary: Lactic Acid 5% + HA
• The Ordinary: Salicylic Acid 2% Solution
• The INKEY List: PHA Toner