Almost everyone gets dark circles under their eyes from time to time. You might be surprised to learn that fatigue is usually not the cause. In fact, nasal congestion is the most common cause of dark circles. When the nose is congested, veins that drain from the eyes to the nose become dilated and appear dark. Another cause is eyelid edema during sleep. When you sleep lying down, gravity causes fluid to accumulate in the lower eyelids, leading to swelling. This swelling creates dark shadows, making you look like you have dark circles. Additionally, skin conditions such as eczema can cause dark circles.
Dark circles are usually temporary and do not generally indicate any serious health problems. You can try using eye creams that contain vitamin C, vitamin K, alpha hydroxy acids, and kinetin to reduce them.