Ingredient caution: salicylic acid/BHA might cause stinging, dryness, peeling, redness and increased sun sensitivity; sulfur/zinc-based oil-control ingredients might feel drying or tight on already dry skin; cleansing surfactants might cause dryness, stinging or tightness if overused; preservatives such as phenoxyethanol/benzyl alcohol might sting very sensitive or compromised skin. Do a patch test before applying. First-time users should start 3–4 times a week, avoid using it with retinol or other exfoliating acids in the same routine, and apply sunscreen daily. Use a moisturiser and reduce frequency if the skin feels tight or flaky. Use lukewarm water, do not scrub, and follow with moisturiser. Do not apply on broken, freshly waxed or irritated skin. Stop use if irritation persists.