Can I layer AHA and BHA on the same night?
You can, but most Korean routines do not stack both acids every night. Alternating nights, or using a mild PHA on off nights, is the lower-irritation default. Same-night layering is for experienced users who already tolerate each acid alone.
More detail
If you combine them, keep contact time short, buffer with a hydrating toner, skip retinoids that night, and use sunscreen the next morning. Stinging that lasts is a stop signal — not a 'working' sign.
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What is the difference between AHA and BHA?
AHAs like glycolic and lactic acid are water-soluble and work on the skin's surface to brighten and smooth, while BHA like salicylic acid is oil-soluble and gets into pores. In Korean skincare both are used sparingly, a few times weekly, always with daily sun protection.
What is BHA and what does it do?
BHA, usually salicylic acid, is an oil-soluble exfoliant that can penetrate pores to dissolve oil and dead skin, helping refine the look of texture and blemish-prone skin. In Korean routines it's used a few times weekly, with sunscreen by day, to avoid over-exfoliating.
✍️ Written & reviewed by the KoreaPlus Editorial team — dermatologist-informed, cosmetic-science researched & source-cited. Last reviewed: 2026-09-07.
General educational information using cosmetic structure-function wording — not medical advice. Always patch-test new actives. © KoreaPlus.