Ingredient caution: vitamin C/ascorbic derivatives might cause tingling, redness or irritation in sensitive skin; niacinamide is usually gentle but might cause tingling or flushing in very reactive skin; glutathione might cause tingling, dryness or redness in sensitive skin; UV filters might sting around the eyes or irritate very sensitive skin. Do a patch test before applying. First-time users should start 3–4 times a week and avoid layering with strong exfoliating acids if the skin stings. 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. Patch test near the jawline first, avoid the eye corners, and remove gently at night. Stop use if irritation persists.