What do we know about

Dark undereye circles

The area under the eyes can appear darker due to constricted blood vessels causing hyperpigmentation or from thinning of the skin around the eyes.
Dark circles are also attributed to tiredness and a lack of sleep. Although this can be one cause, there are other reasons for dark under eye circles, such as allergies or the natural aging process.
In some cases, dark circles under the eyes can indicate a need for lifestyle changes, such as improvements to sleep habits or lifestyle.
These circles are rarely a cause for concern, but people may wish to reduce their appearance for cosmetic reasons.