You have probably heard that undereye darkness is caused by stress or working too hard, or not getting enough sleep. Although all those things may impact your general health, the darkness under your eyes is mostly due to your genetics.
The skin around and under the eye is more thin than others places on your body, and that can mean it is easier to see blood vessels through that thinner layers of skin.
If you are pale skinned, then your veins in that area may look blue because the skin and tissue only lets the blue and violet wavelengths of light reflect back to the eye. Of course, if your natural skin tone is darker, then the blue can mix with your skin pigments and create a green or brown colour reflection. This reflection of the colour from the veins is why bruising around the eyes is sometimes more visible and prominent than bruising on other parts of the body.
Another contributor to darkness under the eyes is hyperpigmentation, which means more melanin [what gives skin colour] is produced by the skin under the eye area. This is more pronounced in those with darker skin and with more average melanin.
Since the majority of darkness under the eyes is connected to melanin and that is controlled mostly by genetics, what does one do about neutralizing the effect? Makeup can change the appearance of the skin and can also help filter or block the dark pigments reflections.
Concealer is usually the product of choice for people who want to cover undereye darkness, and it can work quite well. Choose a formula that gives you the colour, coverage and finish/texture that matches the rest of the skin of your face. Concealers come in many different formulas, from creams to liquids, to hybrids. One important thing to consider when trying different formulas is whether the formula adheres well to the skin without gathering in lines or moving around. Since the skin around the eye moves more than other places on the face, there can be a tendency for some concealer formulas to move into fine lines and folds in the skin, which can draw attention to “laugh” lines. You may have covered the darkness, but now you have exaggerated your lines.
Pick a concealer that filters or neutralizes the blue, so one that includes a slight amount of orange tint pigment will do the trick. Some people think you should pick a shade much lighter than your skin, but this all depends on the amount of coverage in the product. If it has good coverage there is little need to pick a shade lighter than your skin.
Trial and error is usually the best way to test out concealers, but because there are so many to choose from, chances are you can find the best one for you. One way to test the formula without having to try on the face is to place some on the palm of your hand at the base of where the thumb muscle meets the center of the palm. Then move your thumb back and forth to simulate how the skin on your face might move and stretch, to see if the formula tends to gather in the folds of your palm or not. This is also a place where you can see if the coverage is enough to block or filter out the blue or green undertones that may be contributing to your undereye darkness.