Possible causes of dark circles under the eyes
Genetic reasons. If you have naturally very thin and pale skin, then it allows you to see the blood vessels under its surface. Secondly, there is periorbital hyperpigmentation - excessive pigmentation of the surface of the skin around the eyes.
lifestyle factors. Alcohol abuse, smoking, too salty foods, like cortisol, cause blood vessels to dilate.
Age. As we age, the skin loses fat, becoming even thinner and more translucent.
Fatigue. During times of fatigue, lack of sleep or stress, the adrenal glands produce a lot of the steroid hormone cortisol. This hormone not only helps to cope with nervous stress, but also increases the volume of blood pumped through the blood vessels.