Hydroquinone works by inhibiting an enzyme that produces excessive pigmentation. Exposure to the sun, UV rays and sources of injury to the skin such as acne may cause excessive amounts of melanin pigment production. Melanin is the pigment in skin that gives it a brown color. Excessive melanin production may appear as freckles, age spots, post-acne dark marks, cholasma, melasma or general dull appearance. However, hydroquinone is not a permanent correction for dullness, age spots or dark marks. Exposure to UV light will trigger the return of pigmentation.
Avoid exposure to sunlight or artificial UV rays (e.g., sunlamps). Darkening of the skin may occur with exposure to sunlight or artificial UV light. Use a sunscreen (minimum SPF 15) and wear protective clothing when exposure to the sun or UV rays is unavoidable.
Do not use hydroquinone on skin that is sunburned, windburned, dry, chapped, or irritated, or on an open wound. It could make these conditions worse. Wait until these conditions have healed before applying hydroquinone topical.
Hydroquinone is a common ingredient in skin lightening products. It is available over the counter in concentrations up to 2%, and can be prescribed in concentration up to 4%. However, hydroquinone can be very irritating at high concentration and can cause ochronosis (darkening of the skin) with prolonged use. We highly recommend that you be under a physician's care to start out and to have the results monitored.