Dark circles are common and typically appear as discolored areas under the eyes, often giving a tired or aged appearance. They can be caused by a variety of factors, including genetics, thin skin, lack of sleep, stress, allergies, or poor circulation. Sun exposure can also worsen the appearance of dark circles by increasing melanin production. In some cases, they may be a result of blood vessels becoming more visible due to skin thinning or inflammation. Effective treatments focus on improving circulation, hydrating the skin, and brightening the area with ingredients like caffeine, vitamin C, and peptides to reduce puffiness and dark pigmentation.