Thinning eyelashes — causes and treatment options
Quick answer
Eyelash thinning is common and often linked to ageing, hormonal change, eyelid conditions, or how lashes are handled day to day. Gentle care and non-prescription conditioning serums may help a little, while a prescription bimatoprost serum can encourage fuller growth. A clinician can check whether it's suitable for you first.
What causes thinning eyelashes?
Eyelashes naturally thin with age, as fewer follicles stay in their active growth phase at any one time. Hormonal changes, including thyroid conditions and the menopause, can also affect how lashes grow and how quickly they fall out.
Eyelid conditions such as blepharitis (inflammation along the lash line) are a common and often overlooked cause, sometimes alongside dry or irritated eyes. Skin conditions affecting the eyelid, and some scalp conditions that also involve eyebrow or lash hair, can play a part too.
Everyday habits matter as well: rubbing the eyes, harsh removal of eye makeup, and repeated cycles of lash extensions or lash curling can all put strain on the hair follicle over time, particularly if extensions are reapplied before natural lashes have had a chance to recover. Less commonly, hair-pulling conditions such as trichotillomania affect the lash line specifically, and certain medical treatments can cause temporary lash loss as a side effect. For many people, there isn't one single obvious cause — it's a combination of a few of these factors building up gradually rather than a sudden change.
When it's worth speaking to a pharmacist or GP
Occasional lash shedding is normal — each lash has its own growth cycle, lasting several weeks to a few months, and falls out to be replaced by a new one growing underneath. This turnover is easy to miss because it happens gradually across the whole lash line.
It's worth getting checked if thinning is sudden, patchy, or affects one eye much more than the other, or if it comes with redness, swelling, soreness, flaking or crusting along the eyelid margin. These features can point to an eyelid condition that benefits from its own treatment before lash growth will improve.
Lash changes alongside other symptoms — such as persistent tiredness, unexplained weight change, feeling unusually cold, or hair thinning on the scalp or eyebrows — can also point to an underlying thyroid or skin condition that's worth a GP assessment rather than home treatment alone. A pharmacist can help you work out which route makes sense first.
Everyday habits that can help
Simple changes are often the best starting point. Remove eye makeup gently rather than scrubbing, and choose a make-up remover that doesn't need heavy rubbing to shift mascara or eyeliner. Give your natural lashes regular breaks between sets of lash extensions, and try to avoid habitually pulling, twisting or picking at them.
An eyelash curler used daily, especially an old or worn one, can also weaken lashes at the point where it grips — using one less often, or checking the rubber pad isn't perished, is a small change that can help. Keeping the eyelid margin clean, particularly if you're prone to mild blepharitis, can also support healthier lash growth.
Non-prescription lash conditioning serums — typically containing peptides or panthenol — may help lashes look and feel healthier and can reduce breakage, though the evidence for dramatically longer lashes from these products alone is limited. They're a reasonable first step for mild thinning, particularly if there's no underlying eyelid or medical cause identified.
How a prescription eyelash serum works
Where thinning doesn't improve with everyday care, a prescription-only option such as Lumigan (bimatoprost) works differently to cosmetic conditioning serums. Bimatoprost is a prostaglandin analogue that extends the active growth phase of the lash hair cycle and increases the proportion of follicles growing at any one time, which is a different mechanism to simply conditioning the lashes that are already there.
It's applied along the upper lash line at the base of the lashes, usually once a night, using a clean applicator each time to keep the amount used consistent and reduce the chance of it spreading elsewhere. Because it works with the hair growth cycle rather than instantly, it takes sustained, consistent use over a number of weeks before a difference becomes noticeable, and the effect isn't lasting — lashes generally settle back towards their previous pattern over time if the serum is stopped.
Possible side effects to be aware of
The most common effects are mild irritation, redness, itching or dryness where the serum is applied, which often settles as the skin and eye adjust. Some people notice darkening of the skin at the application site, which can fade gradually if the serum is stopped.
A more serious and permanent risk is a change in iris colour — the coloured part of the eye can darken, particularly in people with lighter-coloured eyes, if the serum spreads beyond the lash line onto the eye surface itself. This doesn't reverse. Careful, precise application well away from the eye itself reduces this risk considerably. Unwanted hair growth can also occur on skin the serum touches if it isn't wiped away, and there have been rare reports of eyelid drooping with longer-term use, which has sometimes needed specialist review. Anyone applying it should wash their hands afterwards and avoid letting it run onto the lower lash line, eyelid skin or cheek.
Who a prescription eyelash serum may not suit
A prescription lash serum isn't the right choice for everyone. It generally isn't recommended during pregnancy or while breastfeeding, or if there's an active eye infection or inflammation that needs treating first. People already using prostaglandin eye drops for glaucoma need specific advice, since combining these can increase the overall prostaglandin effect on the eye and may need closer monitoring.
Contact lens wearers, anyone with a history of eye surgery, and people with a personal or family history of eye pigmentation changes or macular conditions should also discuss this with a clinician before starting, so the risks and benefits can be weighed up properly for their particular situation rather than assumed to apply the same way to everyone.
A note on lash extensions and false lashes
Lash extensions and strip lashes are a cosmetic choice many people use alongside, or instead of, any lash treatment, and they aren't harmful on their own when applied and removed correctly. Problems tend to arise from the adhesive used, from extensions that are too heavy for the natural lash, or from picking at extensions rather than having them professionally removed.
If you're using extensions to disguise thinning lashes rather than to enhance already-healthy ones, it's worth having the underlying cause looked at, since extensions can mask gradual lash loss for a while without addressing why it's happening.
Getting started safely
Because of the eye-related risks involved, a prescription eyelash serum should only be started after a proper consultation rather than obtained from an unregulated source online. A clinician can review your eye health history, check for any conditions that would make it unsuitable, and talk through correct application technique to keep the risk of side effects as low as reasonably possible.
If you're unsure whether your thinning lashes need treatment at all, or whether an eyelid condition might be behind them, that's also a reasonable question to bring to a consultation before deciding on any serum, prescription or otherwise.
Frequently asked questions
How long does it take to see results from an eyelash growth serum?
Most people notice early changes from around four weeks of consistent use, with fuller results usually assessed after several more weeks. Results build gradually rather than appearing overnight.
Can eyelash serums permanently change eye colour?
Prescription bimatoprost-based serums have been linked to permanent darkening of the iris, particularly in lighter-coloured eyes, if the product spreads beyond the lash line. This effect does not reverse once it happens, which is why careful application matters.
Are non-prescription lash conditioning serums as effective as prescription ones?
Non-prescription conditioning serums may improve the condition and feel of your existing lashes, but they don't act on the hair growth cycle in the same way a prescription bimatoprost serum does.
Is thinning eyelashes ever a sign of an underlying health condition?
Sometimes, yes. Thyroid conditions, some eyelid and skin conditions, and certain scalp conditions can all affect eyelash growth. It's worth mentioning eyelash changes to a GP if they appear alongside other symptoms such as fatigue, weight change or eyelid swelling.
Can I use a prescription eyelash serum if I wear contact lenses?
Contact lenses usually need to be removed before applying an eyelash serum and can typically be reinserted after a short interval. A clinician can advise on the exact timing for the product you're prescribed.