"Chemical exfoliant" sounds harsh, but it's usually gentler and more even than the gritty scrubs it replaces. The two main families — AHAs and BHAs — get bundled together and confused constantly, yet they do quite different things. Once you know which does what, choosing is easy.
What's the difference between AHA and BHA?
The core difference is where they work: AHAs (like glycolic and lactic acid) are water-soluble and exfoliate the skin's surface — great for tone, texture, and dryness; BHA (salicylic acid) is oil-soluble, so it gets inside pores — great for oil, congestion, and blackheads.
Think of it spatially. AHAs resurface the top layer, sweeping away dull, dead cells for a smoother, brighter look. BHA dissolves into the oil in your pores and clears them from within. Surface versus depth — that's the whole distinction.
Which should you use for your skin?
Match the acid to your main concern: AHA for dullness, uneven tone, fine lines, and dry or normal skin; BHA for oily, congested, blackhead- or breakout-prone skin. Combination skin can use both, in different areas or on different days.
- Dry / dull / uneven tone / early lines → AHA (glycolic for resurfacing, lactic for a gentler, more hydrating option).
- Oily / clogged / blackheads / breakout-prone → BHA (salicylic acid).
- Combination → either, or both — BHA on the oily T-zone, AHA on drier areas.
Our nightly resurfacer Le Renouveau does the renewal work most people want from an exfoliant, without the guesswork of raw acids.
How often should you use an exfoliating acid?
Start once or twice a week and build up slowly — most skin does well with two to three times a week at most. Daily acid use is where over-exfoliation trouble usually begins.
Exfoliation is a case where more is emphatically not better. Begin with one night a week, see how your skin responds, and increase gradually. If you use a leave-on acid, always follow with moisturizer (La Crème) and wear sunscreen the next day — acids increase sun sensitivity.
Can you use AHA and BHA together?
You can, but carefully — using both at once, or too often, is a fast route to over-exfoliation. Most people are better off alternating them (different nights) or using each on the area it suits, rather than layering both every time.
If you want both benefits, alternate: BHA one or two nights for congestion, AHA another night for texture, with recovery nights in between. Layering them simultaneously is only for experienced, resilient skin — and even then, sparingly.
What are the signs of over-exfoliating?
Watch for tightness, stinging, redness, flaking, shininess, and new sensitivity — the barrier waving a flag. If you see these, stop all acids, focus on gentle hydration, and let the skin recover for a couple of weeks.
Over-exfoliation masquerades as "my skin needs more exfoliating" (because it looks flaky), which tempts people to do more — the opposite of the fix. Pull back, cleanse gently with Le Purifiant, hydrate, and reintroduce acids slowly once calm.
FAQ
What is the difference between AHA and BHA? AHAs (glycolic, lactic) are water-soluble and exfoliate the skin's surface for tone and texture; BHA (salicylic acid) is oil-soluble and works inside pores for oil and congestion. Surface versus depth is the key difference.
Should I use AHA or BHA for my skin? Use AHA for dullness, uneven tone, fine lines, and dry or normal skin; use BHA for oily, congested, or blackhead-prone skin. Combination skin can use both, on different areas or different days.
Is salicylic acid an AHA or BHA? Salicylic acid is a BHA — oil-soluble, so it penetrates and clears pores. That's why it's the go-to exfoliant for oily, congested, and breakout-prone skin.
Can I use AHA and BHA together? You can, but carefully — using both at once or too often risks over-exfoliation. Most people do better alternating them on different nights, or using each where it suits, with recovery nights in between.
How often should I use an exfoliating acid? Start once or twice a week and build slowly; two to three times a week is plenty for most skin. Always moisturize after and wear sunscreen the next day, since acids increase sun sensitivity.
Divina's gentle nightly resurfacer, the exfoliation step without the guesswork: Le Renouveau →. Cleanse with Le Purifiant, recover with La Crème.
AHAs work on the surface; BHAs work inside the pore. Match the acid to the problem and exfoliation stops being scary.
