Ingredient caution: retinol/retinoids might cause dryness, peeling, redness, purging and sun sensitivity; 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; fragrance, essential oils or fragrance allergens might trigger redness, itching or allergic irritation. Do a patch test before applying. Retinol is not advised for pregnant or breastfeeding women unless approved by a doctor. First-time users should start 3–4 times a week at night, avoid layering with exfoliating acids, and use sunscreen daily. 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. Stop use if irritation persists.