Ingredient caution: niacinamide is usually gentle but might cause tingling or flushing in very reactive skin; alpha arbutin, glutathione might cause tingling, dryness or redness in sensitive skin; rich oils, butters or occlusive emollients might feel heavy or clog pores in acne-prone/oily skin; preservatives such as phenoxyethanol/benzyl alcohol might sting very sensitive or compromised 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. Use a small amount first and avoid applying on active acne if it feels greasy. Do not apply on broken, freshly waxed or irritated skin. Stop use if irritation persists.