Dark Circles Under Your Eyes: The Four Different Causes

Written by the Skin Project Clinics medical team. Last updated August 2026.

“Dark circles” is one phrase covering at least four different problems. Some are shadows cast by hollowing. Some are actual pigment in the skin. Some are blood vessels showing through skin thin enough to be translucent. And some are simply fluid, tiredness and the time of day. They look broadly similar in the mirror and they respond completely differently to treatment, which is why identifying the cause is the whole job.

Why do dark circles have more than one cause?

The under-eye region is unusually complex for its size. Within a couple of centimetres you have the thinnest skin anywhere on the body, a set of fat compartments that shift and diminish over time, a ligament that tethers skin to bone and creates a groove as the tissue above it thins, pigment-producing cells that respond to sun and inflammation, and a dense network of small vessels sitting just underneath.

Each of those can independently darken the appearance of the area, and they compound. This is why the same person can try three different remedies with no result: not because the products failed, but because each was aimed at a cause they did not have.

It is also why the honest first step is diagnostic rather than therapeutic. Our dark under-eye circles page covers how the area is assessed at the clinic.

Cause one: is it volume loss and tear-trough hollowing?

This is a shadow problem rather than a colour problem, and the distinction matters enormously.

As the mid-face ages, fat pads in the cheek descend and diminish while the tissue immediately under the eye thins. A ligament tethers the skin to the bone along the tear trough, so as volume is lost above and below it, a groove appears. Light falling on the face from above then casts a shadow into that groove, and the eye reads shadow as darkness.

Two clues point to this cause. It usually worsens through the day and in overhead lighting, and it often looks dramatically better in a photograph taken with light from below. It also tends to be accompanied by a general flattening of the cheek, because the same volume loss is producing both.

This is the cause for which volume-based treatment is genuinely well matched, and it is why treatment of this area is discussed at all. It is not, however, the most common cause in isolation. Most people who present with it also have some degree of one of the other three.

Cause two: is it pigmentation in the skin?

This is the cause most often misidentified, and the one most often treated incorrectly.

Constitutional under-eye pigmentation is common and largely genetic. It frequently runs in families, is more prevalent in people with Mediterranean, South Asian, Middle Eastern and other deeper skin tones, and it is often present from a relatively young age rather than developing with time. If you have had dark under-eyes since your teens, this is more likely than volume loss.

Pigmentation can also be acquired, following inflammation in the area. Chronic eye rubbing, allergic conjunctivitis, hay fever and eczema all cause repeated low-grade inflammation, which can leave post-inflammatory pigment behind. Sun exposure contributes as well, and the under-eye area is routinely under-protected.

The practical implication is direct: adding volume beneath pigmented skin does not make pigment lighter. It can improve an accompanying shadow, but the colour remains. Where pigment is the main driver, approaches used elsewhere for pigmentation are more relevant, alongside addressing whatever is causing the inflammation. Our skin rejuvenation page covers skin-quality approaches.

Cause three: are blood vessels showing through thin skin?

This cause is often described as “blue circles”, and the colour is a genuine clue: pigment tends to read brown or grey-brown, whereas vascular visibility tends to read blue or purple.

Skin here is a fraction of the thickness of skin elsewhere on the face, and it thins further over time as collagen declines. When it becomes translucent enough, the underlying vasculature is simply visible through it. Some people have this from a young age because their skin is naturally thin or fair; in others it emerges gradually.

Fatigue and dehydration can make it temporarily more obvious, because vessels dilate, which is part of why this type of darkness fluctuates so noticeably day to day. That fluctuation is itself diagnostic: shadow from hollowing and constitutional pigment are relatively stable, whereas vascular darkness varies with sleep, hydration and time of day.

Approaches here focus on skin quality and thickness rather than volume, and expectations should be measured. Thin skin can be improved somewhat; it cannot be made thick.

Cause four: can sleep, fluid and lifestyle cause dark circles?

Here is the section a cosmetic clinic has the least commercial reason to write, which is exactly why it belongs in the article.

A meaningful proportion of under-eye darkness is not structural at all. Sleep deprivation causes fluid to pool and vessels to dilate. Dehydration and high salt intake do the same. Alcohol contributes on both counts. Allergic rhinitis and nasal congestion produce what is sometimes called an allergic shiner, where impaired drainage causes visible venous congestion under the eyes, and this can be quite pronounced.

The distinguishing feature is variability. If your under-eyes look markedly different on a good week than a bad one, or noticeably better after a holiday, a large part of what you are seeing is in this category. Treating that with an injectable would be treating a fluctuation as though it were a fixed structure.

There is a practical order of operations implied here. Where allergy, congestion or sleep are clearly contributing, addressing them first is both cheaper and more informative, because it reveals what the underlying baseline actually looks like. Deciding on treatment while looking at a temporarily worsened baseline is how people end up treated for a problem they do not have.

How do you tell which type of dark circles you have?

A few simple observations narrow it down considerably, though none of them replaces an examination.

The tilt test is the most useful single check. Tilt your head back and look at your reflection with light coming from below. If the darkness largely resolves, shadow is a significant contributor. If it looks essentially unchanged, pigment or vascular visibility is more likely to be driving it.

The reason this cannot be settled from a photograph, including one you send to a clinic, is that photographs fix a single lighting angle. Assessment involves looking at the area under different lighting, at different angles, and often applying gentle pressure to see how the tissue behaves.

Why does the cause change the treatment completely?

Think of it as four problems at four depths. Volume loss is below the skin. Pigment is in the skin. Vessel visibility is a function of how transparent the skin above them is. Fluid is not a structural problem at all.

An intervention that restores contour beneath the skin will address the first and do essentially nothing for the other three. An approach that improves pigment within the skin will not fill a hollow. Improving skin quality and thickness may help vascular visibility somewhat, and will not resolve a structural groove.

This is the mechanical reason behind an experience many people report: having something done to their under-eyes and finding it made surprisingly little difference. Usually the treatment worked as intended, on a cause that was not the main one.

It also explains why plans for this area are frequently combination plans, and why they are often staged. Treating the dominant cause first and reassessing tells you how much of the remaining appearance is attributable to the others, which is information you cannot get any other way.

When is under-eye filler the right answer, and when is it the wrong one?

The under-eye is one of the areas where the decision not to treat is made most often, and for good reason.

Reasonable candidacy generally means a clear, defined hollow that accounts for most of the darkness, skin with enough thickness and quality to sit well over added volume, an absence of significant fluid retention or puffiness, and realistic expectations about a partial rather than complete change.

The situations where it is the wrong answer are just as specific. Where pigment is the dominant cause, volume treatment does not address the colour. Where there is existing puffiness or fluid retention, adding volume can accentuate it. Where skin is very thin, material beneath it is more likely to be visible or to create irregularity. And where the darkness fluctuates dramatically week to week, the fluctuation itself suggests a physiological rather than structural cause.

Two further points belong in any honest discussion of this area. It is anatomically unforgiving, so conservative amounts are the norm rather than a cautious exception. And material placed here can persist considerably longer than in more mobile areas of the face, which cuts both ways: a good result lasts, and a result you are unhappy with also lasts.

We would rather decline to treat, or suggest addressing a different cause first, than treat an area unlikely to respond well. That is not a reluctance to help; it is the same judgement applied consistently. Our detailed guide to under-eye filler in North Sydney covers candidacy and reversibility in more depth, and our dermal fillers page covers the broader treatment category. Whatever the cause, it starts with someone looking at your under-eye area properly.

This article is general information only and is not medical advice. It cannot be used to assess your individual under-eye area or any specific concern. Treatments in this area are prescription medical treatments that carry potential risks and require a consultation with a qualified practitioner who assesses you individually. Individual results vary and are temporary. Not everyone is a suitable candidate. Skin Project Clinics, North Sydney. (02) 9929 0455.