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.
More detail
AHAs suit dullness and surface texture; BHA suits oily, congested, blemish-prone skin.
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What is the difference between essence and serum?
In Korean skincare, essence is typically a thinner, hydration-focused layer that preps skin, while serum is more concentrated with targeted actives like vitamin C or niacinamide. Essence usually comes first; serum follows. The line between them blurs, and not every routine needs both.
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 2026-06-21.
General educational information using cosmetic structure-function wording — not medical advice. Always patch-test new actives. © KoreaPlus.