Ingredient caution: niacinamide is usually gentle but might cause tingling or flushing in very reactive skin; alpha arbutin might cause tingling, dryness or redness in sensitive skin. Do a patch test before applying. Start slowly if your skin is sensitive and avoid combining too many new actives at once. First-time users should start 3–4 times a week and pair with sunscreen, because pigmentation care works best with UV protection. Avoid during pregnancy or breastfeeding unless your doctor approves. Stop use if irritation persists.