A friend of mine has been inquiring about dark circles under the eyes. This is obviously a sign of stress, age, lack of sleep, hangovers, etc... but what exactly makes 'em dark?
You can tell your "friend" that the skin around the eyes is thinner than the rest of the skin on the face and body, and lacks oil glands to create moisture in the area. As people age, they lose elasticity around the eye area, which contributes to wrinkles, bags, puffiness, and dark circles. Heredity plays a role in determining how badly one is afflicted by these conditions.
There seem to be several theories on what, exactly, that darker stuff is under the thinner skin around the eye area. According to WebMD, many experts think it's melanin (pigment). Another theory is that the dark stuff is actually veins showing through the skin, as suggested in this article from Ivillage. Factors that make dark circles appear worse include lack of sleep, fluid retention, stress, fatigue, allergies, smoking, and diet. The best way to prevent dark circles is to get plenty of rest; drink lots of water; and avoid dehydrating items full of salt, caffeine, or alcohol. Some people suggest sleeping with your head elevated (try using two pillows) to prevent a buildup of fluid in the eye area that may result in dark circles.
So what do you do if you do wake up with a face full of racoon eyes anyway? Basically, anything that will moisturize the area and reduce swelling (ie. something cold) should do the trick. There are about five million eye creams out there, ranging in price from $10 to over $100. Some people swear by cold cucumber slices, chilled teaspoons, or cooled tea bags. And of course, concealer. Ask Gothamist readers, what's your favorite dark circle remedy?