Urban legend tells us that someone with dark circles under her eyes has been up late partying, studying or working. Dark circles are a sure sign of exhaustion and lack of sleep. The NetDoctor website, however, suggests that the most common cause of dark circles is too much pigment in the under eye area. The CNN Health website also debunks this myth by stating that there are many causes for dark circles under your eyes, but fatigue and high living aren't at the top of the list.

According to the Net Doctor website, there are several possible causes for dark circles under the eyes. Lifestyle is one factor; drinking alcohol, smoking and consuming caffeinated beverages can also contribute to dark circles. Other possible causes include sun exposure, thinness of skin tissue, diet, hyperpigmentation and genetics.

Hydroquinone is a skin bleaching ingredient available in over-the-counter as well as prescription cosmetic products. In 1982, the Food and Drug Administration (FDA) recognized hydroquinone as being generally safe and effective. In 2006, the FDA recommended this recognition be withdrawn and more studies be done to test the safety of this ingredient. As of November 2010, studies are currently underway. In the meantime, the FDA leaves hydroquinone available as an over-the-counter product. Alternatives to hydroquinone include: retinoids, azelaic acid, kojic acid, licorice extract, ascorbic acid, and N-acetyl glucosamine, reports a 2007 "Dermatology and Therapy" study reported on PubMed.gov.

Dark circles and other dark spots on the face may be caused by excessive melanin production. Melanin is the dark pigment that gives skin its color. In areas where melanin becomes excessive, dark areas form on the skin. This is often a result of over-exposure to the sun. Hydroquinone prohibits enzyme action within the skin that causes excessive pigmentation to develop. This cosmetic ingredient may lessen the appearance of dark circles under the eyes.

Have your doctor check any dark spots on your skin to make sure they are not cancerous or pose any health risks. Wash the affected area before applying the hydroquinone cream and wash your hands after handling the cream. Use the hydroquinone product as directed on the package or by your doctor. When using hydroquinone, use sunscreen and avoid direct sun exposure.

Hydroquinone may cause allergic reactions in some users. If the area becomes red, itches or forms blisters, immediately discontinue using the product. Do not use products with benzoyl peroxide or hydrogen peroxide while you are using hydroquinone. This can cause dark staining on your skin. The Cleveland Clinic website states that hydroquinone is not suitable for those with darker skin. They recommend Kojic acid if you have darker skin.