Ingredient caution: PHA, glycolic acid/AHA, mandelic acid/AHA, salicylic acid/BHA might cause stinging, dryness, peeling, redness and increased sun sensitivity; fragrance, essential oils or fragrance allergens might trigger redness, itching or allergic irritation; humectants such as hyaluronic acid/glycerin are usually gentle but might feel sticky or tight if not sealed with moisturiser. 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. Avoid this product if you have fragrance allergy, eczema-prone skin or a damaged barrier. Apply on slightly damp skin and follow with moisturiser if dryness occurs. Avoid during pregnancy or breastfeeding unless your doctor approves. Stop use if irritation persists.