Having dark under-eye circles is honestly something I try not to be too bothered about.
A lot of different factors can cause dark under eye circles (see post Dark Eyes Can Be Mysterious).
It can be a combination of dehydration, excessive sun exposure, sinus congestion from cold and allergies, adrenal fatigue, aging, genetics, or just plain old lack of sleep.
In my case, there really isn’t much I can do about it.
I’m certain now that my raccoon eyes are aggravated symptoms of my allergies.
Allergies to my cat.