AHA vs BHA: Which Chemical Exfoliant Does Your Skin Actually Need?
AHA, BHA, PHA or enzymes? Learn which chemical exfoliant suits oily, dry or sensitive skin, how often to use it, and the products to start with safely.
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The exfoliating aisle is a wall of acronyms: AHA, BHA, PHA, LHA, enzymes, percentages, and peels. You know chemical exfoliants are supposed to give you smoother, brighter, clearer skin, but one person swears by the acid that broke someone else out. It is genuinely confusing, and the stakes feel high, because you have heard the horror stories about over-exfoliating.
That worry is fair. Used well, chemical exfoliants are some of the most satisfying products in skincare. Used carelessly, they are one of the fastest ways to irritate your skin and damage your barrier.
The good news is that choosing is simpler than the acronyms suggest. It comes down to what your skin is like and what is bothering you, because the main acids are suited to different jobs.
The short answer: If your skin is oily or you get blackheads, a BHA like COSRX BHA Blackhead Power Liquid is your match. If it is dry, dull, or uneven, an AHA such as Sunday Riley Good Genes All-In-One Lactic Acid Treatment suits better. Sensitive skin should start gentlest, with a PHA or an enzyme. Start slow, and always wear sunscreen.
What is the difference between AHA and BHA?
The simplest way to remember it: AHAs work on the surface, BHA works in your pores.
AHAs (alpha hydroxy acids), like glycolic and lactic acid, are water-soluble. They loosen the bonds between dead cells on the skin’s surface, which smooths texture, brightens dullness, and evens tone. That makes them a natural fit for dry, dull, or sun-affected skin.
BHA (beta hydroxy acid), meaning salicylic acid and its relatives, is oil-soluble. That lets it get through sebum and into the pore itself, clearing the oil and debris that cause blackheads and congestion. That makes it a natural fit for oily and breakout-prone skin.
Two gentler categories round things out. PHAs (polyhydroxy acids, like gluconolactone) are larger molecules that work more slowly and tend to be gentler, which suits sensitive skin. Enzymes (from papaya or pineapple) nibble at dead cells without acids at all, and are often the gentlest starting point.
Skin Realist check: More acid is not more glow. The people with the smoothest skin are usually exfoliating less than you think, a couple of times a week, not scrubbing acids on nightly. If your skin stings, flakes, or looks shiny-tight, that is over-exfoliation, not progress.
Which one are you?
Use this as a quick guide, then pick a product from the matching section below.
| If your skin is… | Your best exfoliant | Why |
|---|---|---|
| Oily, with blackheads or clogged pores | BHA (salicylic) | Oil-soluble, so it clears inside pores |
| Dry, dull, or uneven in tone | AHA (glycolic, lactic) | Smooths and brightens the surface |
| A mix of both | A gentle AHA/BHA combo | Covers surface and pores |
| Sensitive or easily irritated | PHA or an enzyme | Slower, gentler exfoliation |
BHA: for oily, congested skin and blackheads
COSRX BHA Blackhead Power Liquid
COSRX BHA Blackhead Power Liquid is a leave-on BHA built around betaine salicylate, with niacinamide and willow bark, and its file lists it as fragrance-free. It is aimed squarely at blackheads and clogged pores, and it is gentle enough that many people work up to using it several nights a week.
Start a couple of nights a week, apply to clean, dry skin, and follow with moisturizer. Daytime sunscreen is a must.
AHA: for dullness and dry, uneven texture
Sunday Riley Good Genes All-In-One Lactic Acid Treatment
Sunday Riley Good Genes All-In-One Lactic Acid Treatment is a lactic acid (AHA) treatment aimed at dullness and uneven texture, with prickly pear, aloe, and licorice in the mix. Lactic acid is one of the gentler AHAs, which makes this a good entry into surface exfoliation.
One honest caveat: its file lists it as not fragrance-free and flags limonene, citral, and geraniol, plus lemongrass oil. If you are fragrance-sensitive, patch test first. Start once or twice a week in the evening.
→ See the Sunday Riley Good Genes Treatment on Amazon
For mixed concerns: a gentle AHA/BHA combo
COSRX AHA/BHA Clarifying Treatment Toner
If your skin has both dullness and some congestion, COSRX AHA/BHA Clarifying Treatment Toner combines glycolic acid (an AHA) and betaine salicylate (a BHA) at mild levels, with willow bark and apple water, and its file lists it as fragrance-free. It is a low-key daily-style toner rather than a strong peel.
Swipe it over clean skin a few times a week to start. Because it is gentle, it is a good first chemical exfoliant for people nervous about stronger acids.
→ Read reviews and check price on Amazon
For sensitive skin: gentle daily and enzyme options
Dermalogica Daily Microfoliant Exfoliator
Dermalogica Daily Microfoliant Exfoliator is a rice-powder exfoliator that activates into a creamy paste with water, using enzymes (papain) and a little salicylic acid. Its file recommends it for all skin types and says it is gentle enough for daily use.
Because it is a wash-off powder you control, it is a forgiving way to exfoliate more frequently without overdoing it. Massage gently over damp skin and rinse.
Elemis Papaya Enzyme Peel
Elemis Papaya Enzyme Peel uses papaya and pineapple enzymes (papain) for a non-abrasive, acid-free way to smooth dull skin, which can suit those who find acids too stimulating.
Its file lists it as not fragrance-free and flags fragrance, coumarin, and several citrus oils, so patch test if you react to fragrance. Used as directed, it is a gentle, occasional smoothing step.
→ See the Elemis Papaya Enzyme Peel on Amazon
Stronger weekly peels: for experienced users only
Once your skin is used to regular exfoliation, an occasional stronger peel can give a deeper reset. These are not starting points.
Elemis Pro-Collagen Tri-Acid Peel
Elemis Pro-Collagen Tri-Acid Peel is an 8% tri-acid leave-on peel with mandelic and lactobionic acids, which its file says to use no more than two to three times a week, applied for up to 15 minutes and rinsed off. Elemis notes a slight tingling and redness can occur.
Its file lists it as not fragrance-free and includes denatured alcohol, so it suits resilient skin rather than reactive skin. Never layer it with other acids on the same day.
COSRX The AHA BHA PHA LHA 35 Peel
COSRX The AHA BHA PHA LHA 35 Peel is a high-strength 35% multi-acid blend (including glycolic, lactic, gluconolactone, mandelic, and salicylic acids) and its file lists it as fragrance-free. This is a weekly, experienced-user treatment, not an everyday product.
Use it sparingly, strictly as directed, and only when your barrier is healthy. If your skin is currently irritated, this is the last thing it needs.
→ See the COSRX AHA BHA PHA LHA 35 Peel on Amazon
How to start exfoliating without overdoing it
- Pick one product that matches your skin from the guide above. You do not need an AHA and a BHA and a peel.
- Start low and slow: once or twice a week, on clean, dry skin, in the evening.
- Patch test a new acid on your inner arm or jaw for a day before using it on your whole face.
- Do not stack actives. Avoid using acids and retinol on the same night, and do not layer multiple exfoliants.
- Wear sunscreen every morning. Acids increase sun sensitivity, so daily SPF is non-negotiable while you exfoliate.
Mistakes to avoid
- Exfoliating every day because a little felt good. Frequency is where most people go wrong. Build up slowly.
- Mixing acids with retinol or other acids. Combining strong actives is a fast route to a damaged barrier. If your skin is already irritated, pause and read our guide to a damaged skin barrier.
- Jumping straight to a strong peel. Earn your way up from gentle, leave-on exfoliants first.
- Skipping sunscreen. This undoes the point of exfoliating and raises your risk of dark spots.
- Ignoring the sting. Mild tingling can be normal for some peels, but burning, lasting redness, or flaking means stop.
The bottom line
Choosing a chemical exfoliant is really about matching the acid to your skin: BHA for oily and congested, AHA for dry and dull, and a PHA or enzyme when you are sensitive or just starting out. Pick one, use it sparingly, and protect your skin with sunscreen.
If you are not sure where to begin, a gentle option like COSRX AHA/BHA Clarifying Treatment Toner is an easy first step. Explore more acne and exfoliating liquids and face exfoliants, and if exfoliation has already left your skin irritated, start with our barrier repair guide.
Common questions
What is the difference between AHA and BHA?
AHAs are water-soluble and work on the skin's surface to smooth texture and dullness. BHA is oil-soluble, so it can get into pores to clear oil and blackheads. Dry, dull skin tends to prefer AHA; oily, congested skin tends to prefer BHA.
How often should I use a chemical exfoliant?
Start with once or twice a week and build up only if your skin tolerates it. Most people do not need to exfoliate daily, and over-exfoliating can damage your skin barrier.
Can I use AHA or BHA with retinol?
Avoid using strong acids and retinol on the same night, since together they raise the risk of irritation. Alternate them on different evenings instead.
Do I need sunscreen if I use acids?
Yes, and it is not optional. Exfoliating acids make your skin more sensitive to the sun, so daily broad-spectrum sunscreen is essential while you use them.