Independent guide ยท Updated September 26, 2026
Should you exfoliate with AHA or BHA?
AHAs exfoliate the surface, which helps texture, dullness, and dark marks. BHAs get inside the pore, which helps blackheads and oil. Pick the acid that matches your main concern, start slowly, and resist the urge to use both at once.
What each acid actually does
Alpha hydroxy acids, like glycolic and lactic acid, are water-soluble and work on the skin's surface, loosening the bonds between dead cells so they shed. The result is smoother texture, brighter tone, and faded dark marks over time. They are the surface polishers of the acid world.
Beta hydroxy acid, in practice just salicylic acid, is oil-soluble, which lets it travel into the pore itself and dissolve the mix of oil and dead skin clogging it. That makes it the better choice for blackheads, whiteheads, and oily skin generally. Where AHAs improve the surface, BHAs clean out the plumbing.
Match the acid to your skin
Dry or sun-damaged skin with rough texture and dark spots usually does best with an AHA. Lactic acid is the gentler entry point; glycolic is stronger and better for resilient skin. Oily, congested, or acne-prone skin usually does best with salicylic acid, which is why it shows up in so many acne products.
Sensitive skin can use either, but should start with the gentlest option at low concentration: lactic acid around 5 percent, or salicylic acid at 0.5 to 1 percent. Patch test first, introduce on non-consecutive nights, and watch for the difference between mild tingling that fades and burning that does not.
How to start without wrecking your barrier
Begin twice a week in the evening, on clean dry skin, followed by moisturizer. Increase to every other night only if the skin stays calm after two weeks. More frequent is not more effective; the skin can only shed so fast, and pushing past that point gives you irritation instead of glow.
Use sunscreen every morning while exfoliating. Acids increase sun sensitivity, and exfoliating without sun protection trades one problem for a worse one. This is non-negotiable, not a suggestion.
Why you rarely need both
Using an AHA and a BHA together, or alternating them nightly, is the fastest route to over-exfoliation: stinging, redness, flaking, and breakouts that look like the problems you were trying to fix. One acid, used consistently, handles most concerns. If you genuinely have both surface dullness and clogged pores, alternate them by week, not by night, and keep the total exfoliation days the same.
The exception is combination formulas, which pair low doses of each acid in one product. These are designed to be gentler than layering two separate acids, but they still count as exfoliation days. Do not add a second acid product on top of one.
Signs you are overdoing it
Shiny, tight skin that stings when you apply products you have used for months is the classic signal. So are new breakouts in places you do not normally break out, and a waxy look that makeup sits on top of instead of blending into. When these appear, stop all exfoliation for at least a week, simplify to cleanser, moisturizer, and sunscreen, and restart at half the frequency when the skin feels normal again.
Safety limits
Stop for persistent burning, swelling, blistering, or worsening symptoms from any skin product. Pregnancy, prescription medicines, severe acne, and scarring need individualized medical guidance. Introduce exfoliating acids only under a clinician's direction if you use prescription retinoids, and wear daily sunscreen when using any exfoliating product.
Sources
- American Academy of Dermatology: How to safely exfoliate at home (accessed September 26, 2026)
- MedlinePlus: Skin conditions (accessed September 26, 2026)