With any aging population comes the manifestation of skin that includes not only wrinkles, but also hyperpigmentation. Along with this, consider an increased incidence of adult acne often leading to postinflammatory hyperpigmentation and the newest baby boom, which accounts for more melasma among women, and the result is an increased demand for skin-lightening products in the United States.
For many years, hydroquinone has been considered one of the most effective skin-lightening agents for treatment of sun-induced pigmentation, postinflammatory hyperpigmentation, melasma and other forms of hyperpigmentation often associated with aging skin. In the United States, hydroquinone is classified as an over-the-counter (OTC) drug that may be used in concentrations of up to 2%. Most prescription-strength hydroquinone formulations contain 3–4%, but concentrations as high as 10% may be available through compounding pharmacies. When prescribed by a physician, it is often combined with other actives, such as tretinoin, retinol, vitamin C or glycolic acid.
How does hydroquinone work?
There are various theories about how hydroquinone works to affect hyperpigmentation. Some researchers claim that it denatures the melanin-protein complex, causing a decoloration of the skin. Others claim it inhibits the tyrosinase enzyme, as well as the synthesis of the protein associated with melanin. Because of its cytotoxic impact on the melanocyte, it is said to disrupt basic cellular processes, including DNA and RNA synthesis.1,2,3,4 Regardless of the mechanism used to lighten skin, the focus these days should really be on the more important concerns regarding the safety of hydroquinone.