Your question is answered in two other threads on my forum. You can click on "search messages" at the top of my main forum page at www.TheNaturalHealthPlace.com/Forum.html for information on this or whatever other topics may be of interest to you. To save you time I will summarize the previous responses concerning "dark circles under eyes" for you.
Dark circles under your eyes are due to lymphatic congestion. Most people relate this to liver and/or kidney toxic overload. Since there are no muscles under your eyes to absorb excess fluid, this liquid is trapped under the skin surface waiting for lymphatic drainage to clear it. You see this collection of fluid right through your skin.
To reverse as well as prevent these dark circles you need to reduce the toxic load on your kidneys and on your liver. The best thing of all is to drink adequate amounts of pure water that contains no chlorine or fluorine. You can safely drink up to half your body weight in ounces of water every day.
That is an awful lot of water. I certainly do not drink that much. The point is we all could probably benefit from drinking more water every day. And, with dark circles under your eyes, you certainly need to do so.
In addition, to help your liver and kidneys clear and heal, consider drinking one to three, four to six ounce, glasses of freshly made juice from organic vegetables. A really good, cleansing vegetable combination would be one to two ounces of "green" juice (from fresh greens such as kale, chard, and especially spinach) with some cucumber, parsley, celery, beets, and carrots.
Yes, genetics could definitely be a possibility. I only consider the implications of dark circles as part of an overall picture of someone, and what it may imply, if they are experiencing health problems.
Best of Health,