Understanding Dark Circles Under Eyes: Causes and Treatments

What Are Dark Circles and Why Do They Happen

Dark circles under the eyes are darkened or discolored patches of skin that appear below the eye area. They can range in color from purple or blue to brown or black, depending on your skin tone and the underlying cause. The skin under your eyes is thinner than the rest of your face—about 0.5 millimeters thick compared to 2 millimeters on other areas—which means blood vessels show through more easily. When these vessels become dilated or when blood pools in them, the darkness becomes more visible through the thin skin.

Dark circles affect a large portion of the population. Research suggests that approximately 10% of people seek treatment for this concern, but many more experience it without seeking help. Dark circles themselves are not dangerous or a sign of serious illness in most cases, though they can occasionally indicate an underlying health issue worth discussing with a healthcare provider.

The area under your eyes lacks oil glands, which makes it prone to dryness and sensitivity. This region also has limited fat padding compared to other facial areas. As a result, the delicate skin under your eyes is more susceptible to showing signs of fatigue, aging, and other factors that can make dark circles more noticeable.

Several structures work together in this area: the tear trough (a groove that runs from the inner corner of the eye downward), the eye socket, and the muscles that support the eye. Changes in any of these structures can make dark circles appear more prominent.

Practical takeaway: Understanding that dark circles result from thin skin showing underlying blood vessels helps explain why they look worse at certain times and respond to different treatments. The darkness you see is often just your skin being transparent enough to show what lies beneath.

Sleep and Fatigue: The Most Common Cause

Lack of quality sleep stands as the number one reason people develop dark circles. When you don't get enough rest, several changes happen in your body that make dark circles worse. Blood vessels under your eyes dilate and become more visible. Your skin also becomes paler and more translucent when you're tired, which makes the darkness underneath show through even more clearly.

The National Sleep Foundation recommends that adults get 7-9 hours of sleep per night. Studies show that people who consistently get less than this amount report more noticeable dark circles. One study found that just one night of poor sleep can increase the appearance of dark circles within hours. The effect compounds—the more nights you miss sleep, the worse the circles become.

When you sleep, your body performs important maintenance work. Fluid redistributes throughout your body, reducing puffiness. Blood circulation stabilizes. Skin cells regenerate more actively. Without this rest period, these processes don't happen as effectively. Your eyes may also puff up when you're tired, which casts a shadow under the eyes and makes dark circles appear worse.

Sleep quality matters as much as quantity. Fragmented sleep—where you wake up multiple times during the night—can be as problematic as short sleep. Sleep apnea, a condition where breathing repeatedly stops and starts during sleep, is particularly linked to dark circles. People with untreated sleep apnea often have noticeable dark circles because their blood oxygen levels drop repeatedly throughout the night, causing blood vessels to dilate.

Shift work and irregular sleep schedules also contribute to dark circles. Your body follows a circadian rhythm—a 24-hour internal clock that regulates sleep, hormone release, and other functions. When you work nights or have constantly changing schedules, this rhythm becomes disrupted, leading to poorer sleep quality.

Practical takeaway: Improving your sleep schedule may reduce dark circles more than any other single change. Even small improvements—going to bed 30 minutes earlier or keeping a more consistent schedule—can show visible results within a week or two.

Aging, Genetics, and Your Family History

Your genes play a significant role in whether you're prone to dark circles. If your parents had noticeable dark circles, you're more likely to develop them as well. Research on hereditary dark circles shows that some people inherit a tendency toward lighter skin pigmentation in the under-eye area, making blood vessels more visible. Others inherit a tendency toward increased blood vessel visibility in this specific region.

As you age, dark circles typically become more noticeable. The skin loses collagen and elastin—the proteins that keep skin firm and elastic—at a rate of about 1% per year after age 25. This loss is most visible in delicate areas like the under-eye region. The fat pads that support the eye area also decrease with age, causing the skin to sink slightly and creating shadowing that makes circles appear darker.

Age-related changes also affect blood vessels. Over time, blood vessels become more fragile and may leak slightly, causing discoloration. The skin barrier itself weakens with age, making it drier and more transparent. All these changes work together to make dark circles more prominent in older adults.

Ethnic background also influences dark circles. People with darker skin tones may be more prone to dark circles because of how their skin naturally produces and distributes melanin (the pigment that gives skin its color). Post-inflammatory hyperpigmentation—where skin darkens after inflammation or irritation—is more common in people with darker skin. Conversely, people with very fair skin may show dark circles more easily because blood vessels show through their lighter skin more readily.

Some people are born with a genetic tendency toward hyperpigmentation in the under-eye area. This appears as a darker skin tone in the orbital region (the area around the eye) and is sometimes called "periorbital hyperpigmentation." This condition is particularly common in people of African, Asian, Hispanic, and Mediterranean descent.

Practical takeaway: If dark circles run in your family and you've had them since childhood, genetics is likely the primary cause. Understanding this can help you set realistic expectations for treatment and focus on options that work for genetically-based dark circles rather than fatigue-based ones.

Allergies, Inflammation, and Medical Conditions

Allergies represent one of the most common medical reasons for dark circles. When you have allergies—whether seasonal like pollen or year-round like dust mites—your body releases histamine, a chemical that causes blood vessels to dilate and become inflamed. This inflammation and vessel dilation is what causes the itching, redness, and puffiness associated with allergies. The under-eye area, being sensitive and thin-skinned, shows these changes dramatically.

During an allergic reaction, the delicate skin under your eyes becomes irritated. You may rub your eyes more frequently, which causes further irritation and inflammation. This repeated rubbing can even break small blood vessels, leading to slight bleeding that appears as dark purple or blue circles. Allergic shiners—the name doctors use for allergy-related dark circles—are particularly common in children with untreated allergies.

Eczema and other inflammatory skin conditions can also cause dark circles. Atopic dermatitis (eczema) frequently affects the under-eye area, causing itching, redness, and darkening of the skin. People with eczema often have a darker line or crease running through the under-eye area, sometimes called Dennie-Morgan folds, which is actually a skin fold caused by repeated swelling and itching.

Several medical conditions are associated with dark circles. Thyroid disorders, particularly hypothyroidism (an underactive thyroid), can cause fluid retention and puffiness around the eyes. Anemia—a condition where your blood doesn't carry enough oxygen—can cause pale skin and pronounced dark circles because the blood appears darker against paler skin. Liver disease, kidney problems, and nutritional deficiencies can all contribute to dark circles.

Sinus problems and nasal congestion can also cause dark circles. When your sinuses are congested, blood vessels around the eyes and nose become dilated and engorged. This congestion can cast a shadow under the eyes. Chronic sinusitis can create persistent dark circles that last until the sinus condition improves.

Practical takeaway: If dark circles appeared suddenly or are accompanied by other symptoms like itching, redness, swelling, fatigue, or unexplained weight changes, mention this to your healthcare provider. Some dark circles that seem cosmetic may actually signal a medical condition worth investigating.

Lifestyle Factors and Environmental Causes

Several daily habits and environmental