Arbutin and kojic acid: what to know

They are used in products for dark marks and uneven tone. Results tend to develop gradually, and consistent sun protection helps prevent treated areas from darkening again.

Both ingredients reduce steps involved in melanin production, the process that gives skin its colour. Arbutin is a plant-derived compound used in leave-on skincare, while kojic acid is produced through fungal fermentation and is also formulated in creams, serums and cleansers. A product may contain one or both. Combining them does not automatically make a formula more suitable or faster acting.

They target existing areas of excess pigment rather than changing the skin's natural baseline colour. Dark marks can have different causes, so an accurate diagnosis matters before treating a new, changing or unexplained patch.

Patch-test a new product on a small area and follow its label. Introduce one active product at a time so you can identify what causes irritation. Start with less frequent application if your skin is reactive, avoid broken skin and keep the product away from the eyes. A bland moisturiser can reduce dryness.

Use broad-spectrum sunscreen during the day and limit avoidable sun exposure. Do not layer multiple exfoliating acids, retinoids or brightening products at once unless a clinician has helped plan the routine. During pregnancy or breastfeeding, show the full ingredient list to a qualified clinician before use.

Stop the product and seek prompt medical advice if you develop marked swelling, blistering, widespread rash, severe burning, eye exposure with persistent symptoms, or breathing difficulty. For mild stinging, redness or peeling, rinse or stop use and allow the skin barrier to recover; arrange a dermatology assessment if symptoms continue.

A dark area that changes shape or colour, bleeds, develops a sore, or appears without a clear explanation should be examined rather than treated as routine pigmentation.

Ask what is causing the pigmentation, whether arbutin or kojic acid suits your skin type, which other active ingredients should be paused, and how to judge irritation. Bring the product or a clear photograph of its ingredient list to the appointment.