Dark circles form under your eyes because the skin there is the thinnest on your entire body, making everything beneath it more visible. Blood vessels, pigment, and structural changes can all show through that delicate skin, and the specific cause varies from person to person. Most dark circles come from some combination of genetics, aging, lifestyle habits, and vascular congestion rather than a single factor.
Your Under-Eye Skin Is Uniquely Thin
The skin covering your eyelids is thinner than anywhere else on your body. While skin on your back or the soles of your feet can be several millimeters thick, under-eye skin is a fraction of that. This means blood vessels, muscle tissue, and bone structure underneath are far less concealed. When those vessels dilate or when the tissue loses volume, the color change shows up immediately in a way it wouldn’t on your cheek or forehead.
A thin, flat muscle called the orbicularis oculi sits just beneath that skin. It controls blinking and squinting. Because it’s right at the surface, its color and the blood flowing through it contribute to whatever tint you see under your eyes. This anatomy is the same for everyone, which is why nearly all people notice some degree of under-eye darkness at certain times.
The Four Types of Dark Circles
Dermatologists generally classify dark circles into four overlapping categories based on what’s driving the discoloration. Understanding which type you have matters because each one looks slightly different and responds to different approaches.
- Pigmented: Excess melanin in the skin itself creates brown or dark brown discoloration. This is more common in people with deeper skin tones and is strongly tied to genetics and sun exposure.
- Vascular: Dilated or congested blood vessels beneath the skin create blue, purple, or reddish tones. This type is especially visible in people with lighter skin.
- Structural: Volume loss, fat pad shifting, or bone structure creates a shadow that looks like a dark circle but is actually a contour issue. This becomes more prominent with age.
- Mixed: Most people have a combination of two or three of the above, which is why dark circles can be stubborn to address.
Genetics and Skin Tone
Your genes are the single biggest factor determining whether you’re prone to dark circles. The amount, type, and distribution of melanin in your under-eye skin is inherited, and some people simply produce more pigment in that area regardless of their habits. If your parents have noticeable dark circles, you’re likely to develop them too.
Skin color and ethnic background play a significant role. People with darker skin tones tend to have more melanin-driven (brown) dark circles, while people with lighter skin are more likely to see vascular (blue-purple) discoloration showing through. Research across African, East Asian, and European skin types has confirmed that these patterns hold broadly, though individual variation within any group is wide. The circles can appear at any age, including childhood, when genetics is the primary driver.
How Aging Changes the Under-Eye Area
As you get older, several structural changes happen at once in the tissue surrounding your eyes, and they all make dark circles worse. Collagen breaks down, fat pads shrink and shift, and the ligaments holding everything in place stretch out. The combined effect is a hollowing called a tear trough deformity: a visible groove running from the inner corner of your eye down toward your cheek.
This groove forms because the ligaments connecting the muscle and skin to the bone underneath weaken over time. Fat that once cushioned the area either atrophies or slides forward, leaving a depression behind. That depression casts a shadow, which creates the appearance of a dark circle even when there’s no extra pigment or vascular congestion involved. In many older adults, this shadow effect is the dominant cause of under-eye darkness.
The process is gradual. You might first notice it in your mid-30s or 40s, and it deepens over the following decades. Because it’s a volume and structure issue rather than a color issue, topical creams have limited effect on this type of dark circle.
Allergies and Nasal Congestion
If your dark circles look bluish and get worse during allergy season, congested sinuses are likely the culprit. When your nasal passages swell from allergies or chronic sinus problems, blood flow through the veins around your sinuses slows down. Those veins sit close to the surface of the skin directly under your eyes. When they become engorged with backed-up blood, the area looks darker and puffier. Doctors sometimes call this “allergic shiners.”
The mechanism works like a traffic jam. Swollen mucous membranes in the nose and sinuses put pressure on surrounding veins, blocking their normal drainage. The backup spreads to the small veins and blood vessel networks in the lower eyelid, giving the skin a blue or purple cast. This explains why children with chronic allergies often have visible dark circles despite being young and well-rested. Treating the underlying congestion, whether from seasonal allergies, a cold, or chronic sinusitis, typically reduces the discoloration.
Sleep, Stress, and Daily Habits
Sleep deprivation doesn’t directly create pigment under your eyes, but it makes existing dark circles dramatically more visible. When you’re tired, your skin becomes paler, which increases the contrast between the rest of your face and the naturally darker under-eye area. Poor sleep also promotes fluid retention and blood vessel dilation, both of which worsen puffiness and vascular dark circles.
Several other daily factors contribute through similar mechanisms. Smoking and alcohol consumption promote blood vessel stasis, meaning blood pools rather than circulating efficiently through the tiny vessels under your eyes. Even mouth breathing, which is common in people with nasal congestion or during sleep, can worsen the appearance. Conditions that cause fluid retention, including thyroid disorders, kidney problems, and heart or lung disease, also make under-eye puffiness and discoloration more noticeable.
Screen fatigue plays a role too, though indirectly. Staring at screens for long stretches causes eye strain, which increases blood flow to the area around your eyes. Over hours, this can make the vascular component of dark circles more prominent.
Sun Exposure and Pigment Changes
Ultraviolet light triggers melanin production everywhere on your body, and the under-eye area is no exception. Because the skin there is so thin and delicate, even modest sun exposure can cause a noticeable increase in pigmentation. Over time, repeated UV exposure without protection deepens brown-toned dark circles, especially in people already genetically prone to producing more melanin in that area.
Dermatologists recommend UV protection as a baseline maintenance step for anyone concerned about pigmented dark circles. Sunglasses that cover the under-eye area and mineral sunscreen applied close to the eyes both help prevent further darkening.
What You Can Do About Them
Because dark circles have multiple causes, no single treatment works for everyone. The first step is identifying what type you’re dealing with. Brown discoloration points to a pigment issue. Blue or purple tones suggest vascular congestion. A hollow or shadow that shifts when you change the lighting angle is structural.
For pigment-driven circles, topical ingredients that reduce melanin production, like vitamin C, niacinamide, and certain acids, can gradually lighten the area over weeks to months. Consistent sunscreen use prevents the pigment from deepening again. For vascular circles, cold compresses constrict blood vessels temporarily, and caffeine-containing eye creams can reduce puffiness by improving local circulation. Treating underlying allergies or congestion often makes the biggest difference for this type.
Structural dark circles caused by volume loss are harder to address topically. Dermal fillers injected into the tear trough can restore lost volume and eliminate the shadow effect, though results are temporary and require a skilled practitioner. Retinol-based products can modestly thicken skin over time by stimulating collagen, but they won’t replace lost fat or bone volume.
Simple lifestyle adjustments help across all types: sleeping with your head slightly elevated reduces overnight fluid pooling, staying hydrated keeps skin less translucent, and getting consistent sleep of seven hours or more reduces the pallor that makes circles stand out. These steps won’t eliminate genetic dark circles, but they can keep them from looking their worst.