Topic

Chemical exfoliation

An exfoliating acid only works in its free-acid form, and how much of it is free depends on pH — a number almost no brand publishes. That single omission is why two products at the same stated concentration can behave very differently.

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  Formulation science

  Why pH decides whether a 2% BHA does anything

  Two exfoliants can both say 2% salicylic acid and behave completely differently. The variable that separates them is pH — and almost no brand publishes it.

  15 September 2026