Hydroquinone skin lightening products deserves more discussion because it has long been established as the most effective ingredient for reducing and potentially eliminating melasma. Over-the-counter hydroquinone products can contain 0.5% to 2% concentrations of hydroquinone, while 4% (and sometimes even higher) concentrations are available only from a physician.
In medical literature, hydroquinone is considered the primary topical ingredient for inhibiting melanin production. Using it in combination with the other options listed in this section —especially tretinoin—can greatly reduce and even eliminate skin discolorations (Sources: Cutis, March 2006, pages 177-184; Journal of Drugs in Dermatology, September-October 2005, pages 592-597; Journal of Cosmetic Science, May-June 1998, pages 208-290; and Dermatological Surgery, May 1996, pages 443-447). Interestingly, hydroquinone is not only a hero for those with sun- or hormone-induced melasma, but its components have potent antioxidant abilities (Source: Journal of Natural Products, November 2002, pages 1605-1611).
Hydroquinone is a strong inhibitor of melanin production (Source: Journal of Dermatological Science, August, 2001, supplemental, pages 68-75), meaning that it prevents skin from making the substance responsible for skin color. Hydroquinone does not bleach the skin, which is why calling it a bleaching agent is a misnomer as it can’t remove pigment from the skin cell. Hydroquinone can only disrupt the synthesis and production of melanin hyperpigmentation, which is actually true of any skin-lightening ingredient. When you prevent melanin from being generated, as new skin cells are formed and move to the skin’s surface, they do not contain the excess pigment (melanin), therefore reducing or eliminating these darkened areas.
Some concerns about hydroquinone’s safety on skin have been expressed, but the research when it comes to topical application indicates negative reactions are minor or a result of using extremely high concentrations or from other skin-lightening agents such as glucocorticoids or mercury iodine. This is particularly true in Africa where adulterated skin lightening products are commonplace (Sources: British Journal of Dermatology, March 2003, pages 493-500 and Critical Reviews in Toxicology, May 1999, pages 283-330).
According to Howard I. Maibach, M.D., professor of dermatology at the University of California School of Medicine, San Francisco, “Overall, adverse events reported with the use of hydroquinone… have been relatively few and minor in nature…. To date there is no evidence of adverse systemic reactions following the use of hydroquinone. and it has been around for over 30 years in skin-care products.” Maibach also has stated that “hydroquinone is undoubtedly the most active and safest skin-depigmenting substance…” Research supporting Maibach’s contentions was published in the Journal of Toxicology and Environmental Health (1998, pages 301-317). Concern about hydroquinone having carcinogenic properties is mostly from industrial-grade materials and uses. For cosmetic use there appears to be no similar evidence.
Despite hydroquinone’s impressive track record and efficacy, in September 2006, the Food and Drug Administration (FDA) recommended that products containing hydroquinone be sold only with a prescription due to their opinion that it posed certain health risks. The FDA asserts there are animal studies showing it may be a possible carcinogen, and studies from Africa showing risk of a skin disorder called ochronosis (Source: http://www.fda.gov/OHRMS/DOCKETS/98fr/E6-14263.htm).
More than 200 products containing hydroquinone are currently sold in the United States, and, according to Dr. Susan Taylor, founding director of the Skin of Color Center in New York City and assistant professor of dermatology at Columbia University, “Hydroquinone is the gold standard for treating pigmentation disorders and has been for many years. I consider it to be very safe and effective” (Source: Pittsburgh Post-Gazette, Wednesday, September 6, 2006).
I concur. There is abundant research from reputable sources that shows hydroquinone to be safe and extremely effective (Sources: Cutis, August 2006, Supplemental pages 6–19; Journal of Cosmetic Laser Therapy, September 2006, pages 121–127; American Journal of Clinical Dermatology, July 2006, pages 223–230; and Journal of the American Academy of Dermatology, May 2006, Supplemental, pages 272–281). Surprisingly, there is even research showing that workers who handle pure hydroquinone actually have lower incidences of cancer than the population as a whole (Source: Critical Reviews in Toxicology, May 1999, pages 283–330). Research to the contrary was done either using products contaminated with other ingredients or was performed on mice using high concentrations of hydroquinone—and that doesn’t equate to the levels of hydroquinone used in topical, over-the-counter skin-care products. Further evidence that this proposed ban doesn’t make sense comes from the American Academy of Dermatology (AAD), who doesn’t agree with the FDA’s proposal—yet the AAD stands to gain the most if consumers can only obtain hydroquinone products with a dermatologist’s prescription.
The negative research about hydroquinone and the frightening assertions being levied in the media are not related to how this effective ingredient is used in skin-care products sold in the United States. It has been, and still is, the most effective topical agent for fading and/or eliminating sun- or hormone-induced brown skin discolorations.
Because of hydroquinone’s action on the skin, it can be a skin irritant, particularly in higher concentrations of 4% or greater and predictably when combined with tretinoin. Some medications have been created that combine 4% hydroquinone with tretinoin and a form of cortisone. The cortisone is included as an anti-inflammatory. The negative side effect of repeated application of cortisone is countered by the positive effect of the tretinoin so it doesn’t cause thinning of skin and damage to collagen (Source: Drugs in Dermatology, July-August 2004, pages 377-381).
Hydroquinone can be an unstable ingredient in cosmetic formulations. When exposed to air or sunlight it can turn a strange shade of brown. Therefore, when you are considering a hydroquinone product, it is essential to make sure it is packaged in a non-transparent container that doesn’t let light in and minimizes air exposure.
