The real reason you have dark circles

Dark circles are usually caused by anatomy, pigment, visible blood vessels, allergies, swelling or sleep disruption, not by one magic vitamin deficiency. The same under-eye shadow can come from thin skin, a tear trough, melanin, rubbing, hay fever, iron deficiency anaemia, thyroid disease or fluid retention. The useful question is what type of dark circle you have, whether it is new or one-sided, and whether other symptoms point to a medical cause.¹²

The main types of dark circles

The most common mistake is treating every under-eye shadow as the same problem. Dermatology reviews describe several overlapping causes, including dermal melanin, post-inflammatory hyperpigmentation, thin translucent skin, visible veins, tear trough anatomy, eyelid laxity, swelling and lifestyle factors.¹⁴ Most people have more than one mechanism.

If the skin itself is brown or grey-brown, pigment is part of the picture. This is more common in deeper skin tones, after inflammation, or after long-term rubbing. If the colour looks blue, purple or red-brown, blood vessels and thin skin may be more important. If the darkness changes with lighting or improves when you gently stretch the skin, shadowing and hollowing may be the main issue.

The tear trough is a natural groove between the lower eyelid and cheek. With genetics, ageing, weight loss or facial structure, this groove can cast a shadow that looks like pigmentation even when the skin colour is normal. Creams cannot rebuild bone structure or fat pads. This is why expensive eye products often disappoint.

Medical causes not to miss

Allergy is a major under-eye driver. Allergic rhinitis can cause itchy, watery eyes, sneezing, congestion and rubbing.⁶ Rubbing thickens and inflames the skin, worsens pigmentation, and can make veins more visible. If dark circles come with blocked nose, seasonal symptoms, itchy eyes or eczema, allergy treatment may do more than an eye cream.

Iron deficiency anaemia is another common suspect. NHS guidance lists symptoms such as tiredness, lack of energy, shortness of breath, noticeable heartbeats and pale skin.⁵ Anaemia can make the under-eye area look darker by making surrounding skin paler and fatigue more obvious. But iron is not harmless. It should be tested before supplementing, especially in men, postmenopausal women or anyone with possible bleeding.

Thyroid disease can change the face and eyes. An underactive thyroid can cause tiredness, weight gain, dry skin, constipation, low mood, muscle aches and a puffy face in some people.⁷ Thyroid eye disease, more often linked with autoimmune thyroid disease, is a different issue and can cause eye bulging, irritation or swelling. New eye changes with thyroid symptoms deserve medical review.

Kidney-related fluid retention is less common as a cause of ordinary dark circles, but it matters when swelling is new or persistent. NHS nephrotic syndrome guidance describes swelling, often first noticed around the eyes and then around the lower legs, ankles or feet.⁸ Puffy eyes plus foamy urine, ankle swelling, high blood pressure or unexplained weight gain should not be treated as a cosmetic problem.

What tests are worth asking for

If dark circles are lifelong, symmetrical and match family facial anatomy, testing may not add much. If they are new, worsening or accompanied by fatigue, breathlessness, heavy periods, gut symptoms, weight change, hair loss, cold intolerance, swelling, palpitations or poor sleep, a basic medical review is reasonable.

Useful tests can include full blood count, ferritin, B12, folate, thyroid-stimulating hormone, free T4, kidney function, liver function, HbA1c and inflammatory markers if symptoms point that way. The iron and ferritin guide explains why ferritin matters before taking iron, and the thyroid panel guide explains the difference between TSH, free T4 and free T3.

Do not order a huge private panel just because an influencer linked dark circles to "toxins". Match tests to symptoms. Dark circles alone, with no other symptoms and a stable pattern since childhood, are usually a skin and anatomy issue.

What actually helps

Start with the cause. For allergy-driven circles, reduce rubbing, treat hay fever or eczema, and ask a pharmacist or GP about appropriate antihistamines, nasal sprays or eye drops. For sleep-related vascular circles, regular sleep timing, treating snoring or sleep apnoea, limiting alcohol and managing congestion can help. The sleep architecture guide explains why poor sleep quality can show on the face even when time in bed looks adequate.

For pigment, daily sunscreen around the eye area, careful use of tolerated pigment ingredients, and avoiding irritation matter. Strong actives too close to the eye can trigger dermatitis and make pigmentation worse. For hollowing, topical skincare has limited power. Cosmetic camouflage, lighting, or professional assessment for tear trough treatment may be more realistic.

A systematic review of treatments for periorbital hyperpigmentation found a wide range of approaches, but the evidence base is limited and treatment choice depends on the underlying cause.³ That is the honest answer: dark circles are not one condition, so they do not have one fix.

Be careful with harsh routines. Retinoids, acids, vitamin C serums and pigment creams can irritate eyelid skin if they are too strong, used too close to the lash line, or combined too quickly. Irritation can trigger more rubbing and more pigmentation, especially in deeper skin tones. If a product stings, flakes or makes the area darker, stop and simplify.

Also be sceptical of detoxes, liver cleanses and expensive supplement stacks marketed for dark circles. If the true cause is tear trough anatomy, allergy, sleep apnoea, eczema, thyroid disease or iron deficiency, a generic beauty supplement will miss the mechanism. Spend first on diagnosis: light, pattern, symptoms, basic tests when indicated, and a clinician who can tell skin colour from shadow.

Use the insights section to check beauty and supplement claims before spending money, and use Start here if you need to prepare a GP appointment because dark circles come with fatigue, swelling or other symptoms.

When to get checked promptly

Seek prompt medical advice if dark circles or eye swelling are sudden, one-sided, painful, red, associated with fever, vision changes, eye movement pain, trauma, severe headache, weakness, facial droop or confusion. Also get checked if puffiness comes with ankle swelling, foamy urine, breathlessness, chest pain, severe fatigue, unexplained weight loss, night sweats, heavy bleeding or black stools.

The real reason for dark circles is usually not mysterious. It is a visible mix of skin, blood vessels, anatomy, inflammation, sleep and sometimes systemic health. Once you identify the type, you can stop buying random fixes and act on the cause.

This article is educational and does not constitute medical advice, diagnosis, or a treatment recommendation. Medication uses described as “off-label” are not licensed for that purpose in the UK and should only be considered under qualified clinical supervision. Always speak to your GP, pharmacist, or a registered specialist before starting, stopping, or changing any treatment. If you have severe or alarm symptoms - unintentional weight loss, blood in your stool, difficulty swallowing, persistent vomiting, a fever, or severe pain - seek urgent medical care.