Understanding the Culprit

The key to really understanding how to get rid of dark under eye circles is to understand why they are there.   Your eyelid skin is some of the thinnest in your body, only 0.05 mm in thickness compared to places like the palms of your feet which is a whopping 1.5 mm thick.  Because this skin is so thin, it is much more translucent to the blood flow underneath.  This thin skin is also the reason why muscle twitches are so easy to feel and observe when they happen in the eyelid (see this article for a full explanation of those pesky muscle twitches).  Underneath the skin, there are complex and dense layers of vasculature and capillaries, circulating blood and nutrients through the area.  If the blood vessels or capillaries are widened or dilated, then they appear much larger under the skin, resulting in a darker appearance to the thin skin lying over top.  Common causes of vasodilation?

• sleep or inactivation of the sympathetic nervous system (low lights, absence of noises, basically your body at rest)
• allergies (histamine responses in the body can cause vasodilation)
• alcohol
• estrogen (hormone levels fluctuating during pregnancy are a common cause of increased puffiness and dark circles too)
• warm environments

Puffiness usually pairs with that dark purple appearance, and is actually the result of fluid pooling underneath the thin eyelid skin.  Water pools in areas of chronic irritation, or when we are retaining more fluid in general (such as during pregnancy or when hormones are fluctuating more). Inflammatory events like crying, allergies, or frequent eye rubbing (even pressing your eye too firmly against your pillow if you sleep on your face counts!) will increase the amount of fluid retained under your eyelid skin and cause morning puffiness.

How to Fix It

The best way to approach dark circles and puffy eyelids is to understand that it is a normal body response -- there's no way to eradicate it, just to minimize it.  Getting more sleep and avoiding vasodilators like alcohol late at night can help.  If you are in a much deeper sleep when you wake up in the morning, your vessels will be much more dilated because your body was not circulating those sympathetic nervous system hormones and stimulators.  By comparison, if you are getting the sleep you need, by the time you wake up you would have already exited that deepest REM sleep cycle and your sympathetic nervous system naturally will be starting to activate as well.  

Unfortunately getting more sleep and less late nights isn't always feasible, and you definitely can't control your hormones if they are your root culprit for puffy dark circles.  Here are a few key things to try at home for a quick fix:

Use a cool spoon to reduce puffy eyelids by causing those blood vessels to constrict underneath your thin eyelid skin via

• Constrict those blood vessels with a cold compress for immediate reduction in puffiness and dark rings.  Try wrapping a washcloth around an ice cube and holding against the lower lid, or keep a spoon in the refridgerator and gently hold against that lower eyelid socket.  the curve of the back of the spoon is a perfect shape for your lower lid, but just don't press too hard,
• Have a cup of coffee.  Caffeine will immediately jump that sympathetic nervous system into response, resulting in constriction of blood vessels.  
• Treat your allergies.  The under eyelid is a chief reaction spot for allergies, resulting in puffiness and swelling.  There are some great OTC and prescription allergy eye drops on the market to minimize irritation, itching, and puffiness.
• Don't rub your eyes!  Chronic and frequent eye rubbing can cause your skin to get looser and thinner as you manipulate and distort the skin under your fingers.  The stronger your skin is, the less those dilated blood vessels and retained fluids will be visible underneath. 
• Wear sunglasses.  If your skin is more darkly pigmented from years of sun exposure, there is no way to reduce the appearance of dark circles.  Sun protection from a young age can prevent permanent dark spots on the skin and eyelids.
• Stay hydrated. Remember chemistry class where we first learned that osmosis causes water to move to areas that are dehydrated.  If you want to keep fluid from building up underneath the eyelid skin and causing puffiness, we need to keep the body and skin hydrated with good daily water intake, and a good topical moisturizer applied nightly won't hurt either.

• Philosophy Miracle Worker: This retinoid based cream helps boost skin collagen amounts to prevent wrinkles and keep skin thick and resistant to puffiness.  It also contains peptides to stimulate that essential blood vessels constriction and reduce the appearance of darkness under the eyes.
• ORIGINS GinZing Refreshing Eye Cream: This morning cream is a cocktail of natural caffeines and stimulants to get that under eyelid skin and blood vessels awake.  The combination of coffee bean extract and gensing gets the job done.
• Tarte Maracuja-C Brighter Eye Treatment: Based on a strong mix of Vitamin C and antioxidants, this cream is chiefly a wrinkle protector, but also has oat sugars that help tighten eyelid skin to reduce puffiness.
• Shiseido White Lucent Anti-Dark Circle Cream: In addition to ingredients that increase blood vessels circulation and constriction to minimize dark circles, this cream also attacks dark pigmentation from more active melanin production that can result in permanent darkened eyelid skin, either from genetics or old sun damage.  It also leaves a reflective top coat after application that helps reflect light and make skin look brighter.