Ever looked in the mirror and wondered what was the cause of your under-eye circles? Contrary to what you might think, genetic or hereditary factors are more likely to blame than too many late nights or one too many martinis. So, how are you supposed to know what's causing yours and how best to treat them?

In a recent video between journalist Sally Hughes and NYC Dermatologist Dr Dennis Gross, the two debunked some of the myths and confusion surrounding the topic of dark circles. Sally explained, "There's a real conflation that people have between dark circles and eye bags. Lots of women will say, 'How can I get rid of the bags under my eyes?' And I'm like, 'You don't have bags, you have dark circles.'" Sally goes on to clarify that the primary difference is that dark circles "only have a difference in colour, not in the texture of the skin."

So now that you're certain you really are sporting some proper dark circles, how are you supposed to know what's causing them? This is where the doctor steps in:

"I teach people to do a little test on themselves . . . What you want to do is take your skin [under the eye] and gently lift it up. When you lift it up, look at what happens to the colour of the skin at the dark circle. If when you lift it up, off the skin's structures . . . If the pigmentation does not change and it stays brown, it's telling you that pigmentation is the primary problem. If when you lift it up, it all of sudden comes back to a normal colour, you know it's because the skin is too thin and more transparent," explains Dr Dennis.

Genius huh? Not that we'd put it past these two to bestow us with such valuable information.

So, you've performed the eye test (don't pretend you haven't done it already), now what?If you've discovered pigmentation is your issue (colour was still present when lifted off the skin), Dr Dennis recommends using retinol and vitamin c to treat, "If you have pigment, you have to look to bleach it and bring down the melanin. . . Think your retinol, think your vitamin c." he explains.

On the opposite end of the spectrum, if the pinch test showed thin skin to be the cause, Dr Dennis suggests employing products rich in collagen, vitamin c and hyaluronic acid. "Hyaluronic acid is a great way to create more thickness to the skin and more plumpness to lift it off the deeper structures. . . [the veins] that are actually making the skin look darker" he explained.

Ready to tackle those dark circles? Keep reading to shop our list of products perfect for targeting the two different causes of dark circles.