Ingredients
AHA vs BHA vs PHA: Understanding Korean Skincare Exfoliants
How AHA, BHA, and PHA differ in Korean skincare, who might go slowly, and why stacking several exfoliants is often unnecessary.
K Beauty DeskAugust 28, 2026Updated August 29, 2026
Exfoliating acids show up in K-beauty toners, serums, and even some cleansers. The labels say AHA, BHA, PHA, glycolic, lactic, salicylic, gluconolactone. The marketing often says glow, pores, or “glass.”
This page explains the families, not a ranking of bottles. It will not tell you acids cure acne. It will not invent a percentage that is “right” for everyone. If a product page on this site does not list a concentration, we do not invent one.
Three families, in plain language
AHA (alpha hydroxy acids) — water-soluble acids such as glycolic and lactic acid. They are often discussed for the look of surface texture. They can sting, especially on sensitive skin. American Academy of Dermatology patient education notes that glycolic acid and retinol can irritate, particularly on sensitive skin.
BHA (beta hydroxy acids) — salicylic acid is the BHA most people mean. It is often discussed for congestion-prone or oilier routines. Cleveland Clinic describes salicylic acid as a common BHA. It can dry or irritate. A cleanser that lists BHA is still an acid contact — not automatically a full-face treatment.
PHA (polyhydroxy acids) — such as gluconolactone. They are another hydroxy-acid family used for exfoliation. They are sometimes marketed as “gentler.” Gentle on a label is not a guarantee on your face. Stacking PHA with AHA or BHA is still more than one exfoliating family.
You do not need a dedicated page for every acid name. If a catalog tag says aha or bha, that is family-level information. Unknown INCI stays unknown.
Key takeaways
- AHA, BHA, and PHA are exfoliating acid families. They are not interchangeable, and you do not need all three.
- Stronger or more acids is not automatically better. Irritation can look like “purging” when it is just too much.
- Our routine compatibility notes may flag stacking several exfoliants as use-caution or avoid-stacking — not as a chemical ban.
- If you are new to acids, start with one product and give it time. Do not add a retinoid on the same nights until you know how your skin responds.
Typical cosmetic purposes — not medical claims
People reach for these acids hoping for smoother-looking texture, a less dull look, or help with the look of congestion. Results vary. An acid is not a diagnosis and not a prescription.
Niacinamide is not an exfoliant. Ceramides are not an exfoliant. Using a hydrating cream next to an acid can make a routine more comfortable. It does not make the acid non-irritating.
Skin type and beginner notes
- Oily or combination T-zone: a BHA cleanser or occasional BHA leave-on is a possible tool, not a requirement. Do not add a second BHA product because the first did not “fix pores.”
- Dry or sensitive: start without a daily acid. If you add one later, use it less often and keep moisturizer.
- Beginners: one exfoliating product. Wait before adding another acid or a retinoid.
Cleveland Clinic’s public acid education suggests introducing one facial acid and waiting before adding another. We treat that as conservative advice, not as a rule that two acids are chemically forbidden.
Why stacking several exfoliants is often unnecessary
A K-beauty routine can accidentally include:
- A cleanser with BHA
- A toner with AHA
- A “glow” serum with more acid
That is three contacts. Our Phase 5 compatibility engine may return use-caution for AHA + BHA on typical answers, and avoid-stacking for sensitive or beginner answers. That means: consider choosing one exfoliating approach. It does not mean “never mix these ingredients” as a law of chemistry.
The same engine may say use-caution for retinol + AHA or retinol + BHA, and separate-routines when you marked sensitive or beginner. Again: irritation awareness, not a toxicology label.
Stronger is not automatically better
A higher percentage, a lower pH, or three acids in one routine can mean more sting — not more glow. If skin is flaking, burning, or staying red, simplify. Sunscreen in the morning still belongs; some acids can increase sun sensitivity.
How this shows up in a routine
After you build a sequence in Find Your Routine, read the compatibility section. If it flags multiple exfoliants, that is editorial guidance. Products are not silently removed.
In our catalog, examples that carry a BHA tag include the COSRX Low pH Good Morning Gel Cleanser and Beauty of Joseon Glow Serum (which also lists niacinamide). Those are facts on the record, not a recommendation to use both in the same routine.
Common mistakes
- Using an acid toner every morning and a retinoid every night in week one.
- Treating PHA as “not an exfoliant” and layering it with AHA.
- Skipping moisturizer because the acid “should dry oil.”
How to simplify
Pick one exfoliating product or none. Keep cleanser, moisturizer, and sunscreen. Add niacinamide or a ceramide cream as support if you want a quieter leave-on — not as a second peel.
Sources & Further Reading
Summarized in our own words from pages we opened:
Educational content only — not medical advice.
Where to go next
A short routine still comes first — see the beginner routine. If you are pairing acids with other leave-ons, read layering. Find Your Routine may flag stacked exfoliants as a reason to simplify.
Next
Ingredients
Niacinamide in Korean Skincare: Benefits, Uses, and How to Layer It
What niacinamide is in Korean skincare, how people typically use it, who may want to go slowly, and how to layer it without stacking too many actives.
Also in this desk
Related products
Editorial references, not a ranked list. Read the product page for “best for” and “may not suit” notes.
Gel cleanser
COSRX
Low pH Good Morning Gel Cleanser
A rinse-off gel cleanser whose official INCI lists betaine salicylate (a BHA) and tea tree leaf oil. Choose it when you want those materials in the cleanse step — not as a substitute for a leave-on BHA treatment.
- Oily skin
- Acne
Read product notes
Serum
Beauty of Joseon
Glow Serum (Propolis + Niacinamide)
Beauty of Joseon Glow Serum (Propolis + Niacinamide) is a cushiony treatment serum: the brand page names niacinamide, propolis extract, and BHA, and prior catalog notes record brand-stated 2% niacinamide and 0.5% BHA. More treatment than a plain HA serum — not a clinic peel and not a fragrance-free hydrating water.
- Oily skin
- Pores
Read product notes
Serum
Anua
Niacinamide 10 TXA 4 Serum
This may be a useful option if you specifically want a niacinamide serum that also lists tranexamic acid, arbutin, and betaine salicylate. That mix is a treatment, not a hydrating essence, and it is not interchangeable with COSRX The Niacinamide 15 Serum.
- Oily skin
- Dark spots
Read product notes
Serum
Anua
Azelaic Acid 10 Hyaluron Redness Soothing Serum
This may be a useful option if you want an azelaic-acid serum and you accept that the Anua US INCI also lists betaine salicylate. It is relevant to redness conversations as a cosmetic leave-on — not as a prescription and not as proof it will calm every flush.
- Sensitive skin
- Redness
Read product notes
Hydrating toner
S.NATURE
Aqua Oasis Toner
S.NATURE Aqua Oasis Toner is a watery hydrating toner whose US Olive Young INCI lists gluconolactone (PHA), panthenol, allantoin, papaya extract/papain, and multiple hyaluronic acid forms. A hydration-first liquid with a mild listed PHA — not a peel protocol.
- Dry skin
- Dehydration
Read product notes
Explore more
Find Your Routine
Build your routine
Korean skincare is easier when the steps match your skin, not a generic ten-item list. Find Your Routine turns your answers into a short morning and evening starting point.
Educational content only — not medical advice, a diagnosis, or a guarantee of results. Read our skincare disclaimer.