What is it: Dark circles under the eyes and the most effective ingredients
Anyway while you try to figure out the best way to free flow nasal passages, there are some creams that may help diminish the appearance (but not the underlying cause). There are also some ingredients to avoid. Actually hemorrhoid cream will help a bit because its purpose in life is to constrict swollen blood vessels. But it smells disgusting, usually contains petrolatum and is way too harsh for under-eye skin. Retinol users beware. Over use can cause the skin tissue to become 'vascular' and over stimulate the capillaries.
Vitamin C and or K will help. However, both of these can be drying and should be combined with good moisturizing ingredients. A good eye cream that helps to build up collagen - under-eye skin is particularly thin - is a good idea. Although I haven't personally tried it, Skinergizer's Nourish Dark Circles Eye Cream might be worth a try. It has vit C and K (plus E and A, for that matter). There is sodium hyaluronate to keep in moisture, not to mention emu oil. Nourish also has anti-oxidants in the form of grape, green tea and willow bark. The preservative, sodium hydroxy methyl glycinate, is non-irritating and non-toxic.
Some dark circle treatment creams use chrysin as an active ingredient. This comes from passionflower and has been shown to have anti-inflammatory properties. Haloxyl is a combination of four ingredients: the peptides that make up matrixyl 3000 and two that are supposed to control blood pigmentation. They do seem plausible since the two color degradation elements in hemaglobin are bilrubin and iron. Chrysin, from passionflower, stimulates the enzyme that clears out bilrubin while hydroxysuccinimide makes the iron soluble so that it can be eliminated. Haloxyl is in an eye cream called YBF Correct that I have been trying out and am very impressed with.
If you feel the need to get out the heavy artillery to send your bags packing, you can try laser treatments. This usually involves both a Q-switched ruby laser to get rid of the dark pigmentation and a pulsed dye laser for the blood vessels.