Eyebrow Loss: The Main Causes of Brow Thinning and What You Can Do

Written by Dr Tom Walker | Last reviewed 08/05/2026

Eyebrow loss or eyebrow thinning is common, especially as we get older. For some people it appears gradually, with the brows becoming finer and less defined over several years. For others brow loss happens more suddenly after illness, medication, chemotherapy, over-plucking, nutritional stress or thyroid disease.

At Opti Laboratories we specialise in eyelash and eyebrow growth. Since 2007, we have helped clients with many different types of eyebrow loss from cosmetic thinning to brow loss after thyroid problems, chemotherapy and medication-related shedding. This page gives a clear overview of the main causes, then links to more detailed articles where appropriate.

The important point is that eyebrow loss is not one single condition. The right approach depends on the underlying cause. In many cases, the follicle is still present and regrowth can be supported once the trigger has been addressed.

What causes eyebrow loss?

Eyebrow loss can be caused by local damage to the brow hairs or follicles, disruption of the normal hair growth cycle, medical illness, nutritional deficiency, hormone changes or medication side effects. Sometimes more than one factor is involved. For example, a woman in her fifties may have age-related thinning, mild thyroid imbalance, a history of over-plucking and increased fragility from cosmetic treatments. The most common causes include ageing, repeated over-plucking, nutritional deficits, thyroid disease, chemotherapy and side effects of medicines. Less common causes include autoimmune disease, skin inflammation, trauma, infection and compulsive pulling or rubbing.

Ageing and eyebrow thinning

Ageing is one of the most common reasons eyebrows become thinner. With time, the eyebrow growth cycle can slow, the hairs can become finer, and fewer follicles may remain in the active growth phase at any one time. The change is usually gradual. Many people notice that their brows lose density, shape and definition, particularly after menopause. This type of brow loss is often not dramatic, but it can still alter facial expression. Brows frame the eyes and help define the upper face, so even modest thinning can make the face look more tired or less structured.

Over-plucking and cosmetic trauma

Over-plucking is a classic cause of eyebrow loss. Occasional tweezing is unlikely to cause permanent problems, but repeated removal of the same hairs over months or years can weaken the follicle and alter the normal growth cycle. In some people, the hair gradually grows back finer. In others, parts of the brow may stop regrowing properly.

Nutritional deficiencies

Eyebrow growth depends on the body having enough protein, iron, zinc, vitamin D, B vitamins and other nutrients needed for normal hair production. When intake is too low, or when rapid weight loss places the body under stress, the hair cycle can be disrupted. This can cause shedding or poor-quality regrowth. Nutritional brow loss is often part of a wider picture. People may also notice scalp shedding, brittle hair, fatigue, poor skin quality or slower recovery after illness. This is one reason eyebrow loss should not always be treated as purely cosmetic. If brow thinning is sudden, marked or associated with other symptoms, medical review is sensible.

Thyroid disease

Thyroid disease is one of the best known medical causes of eyebrow loss. Hypothyroidism, or an underactive thyroid, is particularly associated with thinning of the outer third of the eyebrow. This pattern is sometimes called the Queen Anne sign or Hertoghe’s sign. Thyroid hormones help regulate the hair growth cycle. When thyroid hormone levels are too low or too high, follicles may spend less time in the active growth phase and more time resting or shedding. The result can be brow thinning, scalp hair shedding, dry hair, brittle hair or slower regrowth. Thyroid related eyebrow loss should be managed medically first. Once thyroid levels are stable, cosmetic regrowth support may help improve brow density and definition. We have helped thousands of people regrow eyebrow hair lost from thyroid related conditions.

Chemotherapy and cancer treatment

Chemotherapy commonly results in eyebrow loss as a side effect because many chemotherapy drugs affect rapidly dividing cells, including the cells involved in hair production. Brow loss may occur alongside scalp hair loss and eyelash loss, although the timing and severity vary depending on the drug, dose and treatment schedule. In most cases, eyebrows begin to recover after treatment finishes, but regrowth can be slow. Some people find their brows return thinner, lighter, patchier or with a different texture. Taxane chemotherapy drugs, such as docetaxel and paclitaxel, are particularly associated with hair and brow changes in some patients.

Medication side effects

Some medicines can contribute to eyebrow loss or general hair shedding. This is usually through a process called telogen effluvium, where more hairs than usual shift into the resting and shedding phase. The effect is often temporary, but it can be distressing. Medicines that may be linked with hair or brow thinning include some antidepressants, anti-epileptic medicines, retinoids, blood pressure medicines, anticoagulants, cholesterol-lowering medicines and hormone-related treatments such as tamoxifen or aromatase inhibitors. These medicines are often important or essential, so they should not be stopped without medical advice.

Inflammation, mites and skin conditions

Eyebrow loss can also occur when the skin around the brow is inflamed. Eczema, psoriasis, seborrhoeic dermatitis, rosacea and infection can all disturb the follicle environment. Around the eyelids, chronic blepharitis and Demodex mite overgrowth can contribute to lash and brow problems. In these cases, the priority is to treat the underlying inflammation or irritation. Applying growth products to inflamed or infected skin is usually not the correct first step. The skin and follicle environment need to be healthy enough to support regrowth.

Trichotillomania, rubbing and pulling

Eyebrow loss can be caused by repeated pulling, rubbing or scratching. Trichotillomania is a behavioural condition where a person repeatedly pulls out their own hair, often from the scalp, lashes or brows. Trichoteiromania is different: it involves repetitive rubbing rather than deliberate pulling, and can lead to broken, uneven or thinned hairs. These conditions need a careful approach. Cosmetic regrowth support may help once the pulling or rubbing is controlled, but it does not treat the underlying behaviour. Behavioural strategies, psychological support and medical review may be needed.

Can eyebrow loss be reversed?

In many cases, yes. Eyebrow loss can improve if the follicle is still alive and the underlying trigger is corrected. This may involve stabilising thyroid disease, improving nutrition, recovering after chemotherapy, reducing trauma from plucking or treating inflammation. Once the cause has been addressed, the majority of people find that their eyebrows return to normal. It may take a long time, sometimes a few years, but the body does have an amazing healing ability. Unfortunately some people find that their brows do not return to their fullest, or that recovery is slow. Treatments that support the eyebrow growth cycle may help improve density and visible fullness. The most important point is to identify the likely reason for the brow loss before choosing a treatment to help speed up or improve the recovery.

When should eyebrow loss be checked by a doctor?

You should consider medical advice if eyebrow loss is sudden, patchy, one-sided, associated with redness or scaling, linked with scalp hair loss, or accompanied by symptoms such as fatigue, weight change, cold intolerance, heavy periods, skin changes or new medication use. Eyebrow loss is often cosmetic, but it can sometimes be a visible clue to an underlying health issue. A doctor may consider blood tests such as thyroid function, ferritin, vitamin D, B12, folate and inflammatory markers depending on the situation.

How Opti Laboratories can help

Opti Laboratories is a doctor led UK company specialising in eyelash and eyebrow growth. We have helped clients with eyebrow loss after thyroid disease, chemotherapy, over-plucking, medication-related shedding, nutritional stress and cosmetic thinning. Our role is to support cosmetic regrowth once any underlying medical cause has been addressed. We focus on scientifically credible treatments, careful application and long-term brow health rather than short-term cosmetic claims.

Supporting Lash and Brow Recovery

Once any underlying medical or nutritional cause has been addressed, many people want to regrow their lashes and eyebrows.

Opti Laboratories are the eyelash and eyebrow growth experts. We believe that night time behaviours are under-recognised and that simple interventions can make a measurable difference.

Our clients include individuals recovering after:

▪️Thyroid related brow loss
▪️Chemotherapy related eyelash thinning
▪️Trichotillomania and related issues
▪️Cosmetic over plucking
▪️Eyelash and eyebrow loss from radiotherapy
▪️Thinning eyelashes due to medications

However, we also help a lot of people that simply want longer eyelashes and thicker eyebrows too.

Based in the UK and led by a team of British doctors, we have helped thousands of clients. since 2007 and we have been recognised in UK newspapers and magazines.

We continue to innovate. Our award-winning daytime lash and brow serum, the first in the world to offer UV protection for lashes and brows, supports growth and helps protect fragile follicles during your recovery.

This article is intended for educational purposes and does not replace individual medical assessment. Persistent or unexplained eyelash or eyebrow loss should be evaluated by a qualified healthcare professional.

Dr Tom Walker

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FAQ: Eyebrow loss

What is the most common cause of eyebrow loss?

The most common causes of eyebrow loss are ageing, repeated over-plucking, thyroid disease, nutritional deficiency, chemotherapy and side effects of medicines. In many people, more than one factor is involved.

Can eyebrow loss grow back?

Yes, eyebrow loss can often grow back if the follicle is still active and the underlying cause has been corrected. Regrowth is usually slow because eyebrow hairs have a short growth phase and a cycle measured in months rather than days.

Can thyroid problems cause eyebrow loss?

Yes. Hypothyroidism is a well-known cause of eyebrow loss, especially thinning of the outer third of the brow. This pattern is sometimes called the Queen Anne sign or Hertoghe’s sign.

Can over-plucking cause permanent eyebrow loss?

Repeated over-plucking can sometimes cause long-term or permanent eyebrow thinning, especially when the same follicles are traumatised over many years. In milder cases, the brows may recover once plucking stops, although regrowth can take several months.

Can medication cause eyebrow loss?

Yes, some medicines can contribute to eyebrow loss or general hair shedding. This can happen with certain antidepressants, retinoids, blood pressure medicines, anticoagulants, hormone treatments and other drugs. You should not stop prescribed medication without speaking to your doctor.

What vitamin deficiency causes eyebrow loss?

Low iron, zinc, vitamin D, B12, folate or inadequate protein intake can contribute to eyebrow thinning in some people. Nutritional causes are more likely when brow loss occurs with scalp shedding, fatigue, dietary restriction, rapid weight loss or illness.

What should I do if my eyebrows are falling out?

If your eyebrows are falling out suddenly, unevenly or with other symptoms, you should speak to a doctor to look for causes such as thyroid disease, nutritional deficiency, skin inflammation or medication effects. Once the cause is addressed, cosmetic regrowth treatments may help improve brow density.