Lash science · The natural lash
Health: keeping and improving natural lashes
Most of what is sold for lashes has little evidence behind it, and the one product with strong evidence is a prescription drug with side effects. What does help is less exciting: a clean lid margin, gentle removal, and patience measured in months.
A clean lid
The least exciting measure has the best support
Chronic inflammation of the lid margin, blepharitis, is the condition most often found where lashes are lost.5
A review of 34 trials found that cleaning the lids may ease the symptoms of blepharitis, though nothing has been shown to cure it, and that many commercial lid products are sold without real proof that they work. International reports on dry eye say the same of many lid treatments.123
In the one head-to-head trial, 43 people cleaned one eye with a cleanser made for eyelids and the other with diluted baby shampoo for four weeks. Both helped. Only the dedicated cleanser reduced a marker of inflammation, and baby shampoo was linked to weaker mucus cells on the eye.4
At the atelier
A clean lash line is the first thing we check and the first thing we teach. With extensions it matters more, not less.
Cleansers, in the libraryWhat the evidence supports
- Cleaning the lid margin
- may ease symptoms, review of 34 trials
- A cleanser made for eyelids
- better than baby shampoo in one trial of 43 people
- Commercial lid products
- mostly sold without substantial evidence
- A cure for chronic blepharitis
- not shown for any treatment
Mites
Tea tree oil, and a drop that was trialled properly
Lash mites are normal residents, and many people who carry them have no symptoms. Too many are linked to blepharitis, and to lashes lost or growing the wrong way.7
Tea tree oil is the popular remedy. A review of six trials could not say with confidence that it works, and advised lower strengths to avoid irritating the eye. In the laboratory, 1 percent of its active ingredient killed all the oil-gland cells of the lid within 90 minutes, and it is a known skin allergen. In one clinic, people already using tea tree oil were more likely to have signs of mites, not less.689
A prescription drop for mite blepharitis was approved in the United States in 2023. In its two main trials, about half the people treated reached a clear lid margin at six weeks, against one in ten on the inactive drop.1011
At the atelier
We do not treat blepharitis, and we will not sell you a tea tree oil cure. If your lid margin is red, crusted or itchy, that is a visit to an optometrist before a lash appointment.
Clear lid margin after six weeks, two trials pooled
833 people. The trials were sponsored by the drug's maker.
Mascara
Mascara, removal and curlers
Among 128 young mascara users, 19 percent reported lashes falling out, and those who did had worn mascara for longer. The highest rate, 27 percent, was in people who took waterproof mascara off with water alone.13
Lashes from women who wore mascara more often showed more cracking inside, in an imaging study of 36. Eyelash curlers showed no measurable effect, and an earlier study found no outward change in lashes from eye makeup. All three studies are small.1415
Every kind of remover, oil-based, oil-free or micellar, gets under the lid and speeds evaporation of the tears, oil-based ones most. After three months of daily use, 36 percent of mascara tubes in one study grew microbes. Makers usually advise replacing mascara every two to four months.81617
At the atelier
With extensions you do not need mascara, and you should not use it on them. On natural lashes, take it off gently and fully, and replace the tube every few months.
Makeup and extensions, in the libraryThree small studies, in percent
Self-reported in 128 students, and 33 tubes in a pilot study. Neither had a control group.
Loss
When lashes fall out, it is a sign
Lash loss is a sign, not a diagnosis. The causes run from skin disease and infection to thyroid problems, autoimmune hair loss, medicines, inherited conditions and injury. The first question a doctor asks is whether the follicles are scarred, because that decides whether lashes can grow back.185
Loss can be the first sign of an overactive thyroid. Compulsive hair pulling shows as gaps with lashes of uneven length and no inflammation. Among breast cancer survivors who had chemotherapy, 87 percent reported losing lashes.519
Severe zinc or biotin deficiency can cause it. Iron's role is possible but unproven.5
At the atelier
If you arrive with new gaps or uneven loss, we will not cover them with a set. We will tell you what we see and suggest you have it checked first.
Causes a doctor looks for
- Inflammation
- chronic blepharitis, the most common
- Hormones
- an overactive or underactive thyroid
- Autoimmune
- alopecia areata
- Behaviour
- compulsive hair pulling
- Treatment
- chemotherapy and radiotherapy
- Diet
- severe zinc or biotin deficiency
A list, not a way to diagnose. New or patchy loss belongs with a doctor or optometrist.
The approved drug
One product has strong evidence, and it is a drug
Bimatoprost was approved as a glaucoma drop in 2001. Patients noticed longer, darker lashes, and the same 0.03 percent solution, brushed on the upper lid margin, was approved for thin lashes in the United States on 24 December 2008.2021
In its main trial, 278 adults used it or an inactive solution nightly for 16 weeks. Lashes grew 25 percent longer against 2 percent, 106 percent fuller against 12, and 18 percent darker against 3. Little showed before two months. After chemotherapy, lashes also came back without it: half of those on the inactive solution improved by six months, against four in five on the drug.202224
It is not permanent. In a year-long trial, people switched to the inactive solution kept the effect for about two months, then lost most of it by four to six. Its label lists itching, redness and darker lid skin, warns that brown colour added to the iris is likely permanent, and records reports of fat loss around the eye. Studies of lid-line use found iris change rare. A 2026 analysis, mostly of glaucoma drops, found three times the risk of a hollowed upper lid compared with a related drug, and an independent review argues the lash trials probably under-counted both risks.2420252627
After 16 weeks, against the inactive solution
From the drug's label: the main trial, 278 adults. Sponsored by the maker.
The shape of the year-long trial's result for people switched to the inactive solution, redrawn.
At the atelier
That is a conversation for your doctor, not a lash artist. We will tell you what the evidence says about it, and we work happily with clients who use it.
The one drug that works only works while you use it.
In the long trial, most of the gain was gone four to six months after stopping.
Serums
What is in a cosmetic lash serum
Many cosmetic lash serums contain drug-like ingredients of the same family. A 2026 survey of 79 lash-growth cosmetics found about 30 percent did.28
Canada prohibits these ingredients in cosmetics and has recalled serums that contained them. In February 2026 the European Union's scientific committee concluded that none of the three it reviewed can be considered safe in lash or brow products. A legal ban is a separate later step.303133
Everything else has thin evidence. Peptide serums have been tested only without a comparison group, in about 30 women each. Biotin helped hair or nails in 18 reported cases, all with an underlying disorder. No study has tested castor oil for lash growth. And in a small study of one cosmetic serum of the drug family, the tear film broke up about four seconds sooner after six weeks.353637834
At the atelier
Read the ingredient list. An ingredient ending in -prost is a prostaglandin analogue, and in Canada it is not allowed in a cosmetic.
2007
United States
The FDA has a cosmetic lash product containing bimatoprost seized as an unapproved drug.29
Often said
What the evidence shows
Castor oil grows lashes.
No study has tested it. It helped the signs of blepharitis in one small trial, which is a different thing.812
Peptide serums are clinically proven.
The studies had no comparison group, and say themselves that controlled trials are needed.3536
Eyelash curlers break lashes.
Not measured. The one structural study saw no significant effect.14
Lifts, tints and time
Lifts, tints, and the pace of a lash
A lash lift reshapes the lash chemically for about six to eight weeks. The harms reported are irritation and allergy; the first published infection after a lift appeared in 2021. No study has measured what a lift does to the structure of a lash.839
Permanent lash dyes have caused serious eye injuries, according to the FDA, and PPD, the classic hair-dye allergen, has caused severe reactions after salon tints. In Canada, coal-tar dyes are not permitted around the eye. Silver-based tint used at home for years has left permanent deposits in the eye, and in one clinic lash dye use was more common among people with allergic eye disease, though most of those dyes were homemade.1740304142
Lashes grow shorter, finer and lighter with age. Recovery from any loss is paced by the cycle, in months, and follicles that are destroyed do not come back.43238
At the atelier
Patience is the honest prescription. Give natural lashes a full cycle to show what they can do before deciding anything about them.
Recovering lashes, in the libraryAt the atelier
Looking after the lashes under a set
A free 30-minute consultation comes first. We look at your natural lashes under magnification and tell you honestly whether they are ready for a set.
- Every day
- clean the lash line
- Every few months
- a new mascara, if you wear it
- Anything new
- a doctor before a lash artist
Sources
Every numbered line above comes from one of these. Where a claim is still a hypothesis, the text says so.
- 1Interventions for chronic blepharitisLindsley, Matsumura, Hatef and Akpek. Cochrane Database of Systematic Reviews, 2012.Systematic review: 34 trials
- 2TFOS DEWS II management and therapy reportJones, Downie, Korb and colleagues. The Ocular Surface, 2017.International consensus report
- 3TFOS DEWS III: management and therapyJones, Craig, Markoulli and colleagues. American Journal of Ophthalmology, 2025.International consensus report
- 4Randomized double-masked trial of eyelid cleansing treatments for blepharitisSung, Wang, Lee, Cheung, Ismail, Sherwin and Craig. The Ocular Surface, 2018.Randomized trial: 43 people
- 5Madarosis: a marker of many maladiesKumar and Karthikeyan. International Journal of Trichology, 2012.Review of the published research
- 6Tea tree oil for Demodex blepharitisSavla, Le and Pucker. Cochrane Database of Systematic Reviews, 2020.Systematic review: 6 trials
- 7Demodex blepharitis: a comprehensive review of the disease, current management, and emerging therapiesRhee, Yeu, Barnett and colleagues. Eye and Contact Lens, 2023.Review; authors tied to a drug maker
- 8TFOS Lifestyle: impact of cosmetics on the ocular surfaceSullivan, da Costa, Del Duca and colleagues. The Ocular Surface, 2023.International consensus report
- 9The prevalence of Demodex blepharitis in US eye care clinic patients as determined by collarettesTrattler, Karpecki, Rapoport and colleagues. Clinical Ophthalmology, 2022.Measured: 1,032 clinic patients
- 10Safety and efficacy of lotilaner ophthalmic solution 0.25% in treating Demodex blepharitis: pooled analysis of two pivotal trialsYeu, Paauw, Vollmer and colleagues. Ophthalmology and Therapy, 2025.Two randomized trials, 833 people; maker-sponsored
- 11XDEMVY (lotilaner ophthalmic solution) 0.25%, prescribing informationTarsus Pharmaceuticals. DailyMed, US approval 2023.Drug label
- 12Randomized trial of topical periocular castor oil treatment for blepharitisMuntz, Sandford, Claassen and colleagues. The Ocular Surface, 2021.Randomized trial: 26 people
- 13Mascara induced milphosis, an etiological evaluationKadri, Achar, Tantry, Parameshwar, Kudva and Hegde. International Journal of Trichology, 2013.Questionnaire: 128 users
- 14Internal structure changes of eyelash induced by eye makeupFukami, Inoue, Kawai, Takeuchi, Uesugi and Suzuki. Journal of Cosmetic Science, 2014.Measured: 36 women, a correlation
- 15Ethnic characteristics of eyelashes: a comparative analysis in Asian and Caucasian femalesNa, Kwon, Kim, Park, Oh, Kim, Cho and Eun. British Journal of Dermatology, 2006.Measured: 30 women
- 16Microbial contamination associated with mascara usePack, Wickham, Enloe and Hill. Optometry, 2008.Pilot study: 33 tubes
- 17Eye cosmetic safetyUS Food and Drug Administration. FDA, 2022.Regulator
- 18MadarosisKhong, Casson, Huilgol and Selva. Survey of Ophthalmology, 2006.Review of the published research
- 19Madarosis among breast cancer survivorsPremji, Ruddy, Larson and colleagues. Clinical Breast Cancer, 2024.Survey: 838 survivors
- 20LATISSE (bimatoprost ophthalmic solution) 0.03%, prescribing informationAllergan. DailyMed, label of December 2025.Drug label
- 21Drugs@FDA: LATISSE, NDA 022369US Food and Drug Administration. Approved 24 December 2008.Regulator
- 22Eyelash growth in subjects treated with bimatoprost: a multicenter, randomized, double-masked, vehicle-controlled, parallel-group studySmith, Fagien, Whitcup and colleagues. Journal of the American Academy of Dermatology, 2012.Randomized trial: 278 adults; maker-sponsored
- 23The eyelash follicle features and anomalies: a reviewAumond and Bitton. Journal of Optometry, 2018.Review of the published research
- 24Long-term safety and efficacy of bimatoprost solution 0.03% application to the eyelid margin: a randomized controlled trialGlaser, Hossain, Perkins and colleagues. British Journal of Dermatology, 2015.Randomized trial, one year; maker-sponsored
- 25A retrospective review and observational study of outcomes and safety of bimatoprost ophthalmic solution 0.03% for treating eyelash hypotrichosisYoelin, Fagien, Cox and colleagues. Dermatologic Surgery, 2014.Chart review: 585 users; maker-sponsored
- 26Periorbital fat atrophy with topical bimatoprost: systematic review and meta-analysisSheather, Kailani, Qureshi, Somani, Han and Somani. Ophthalmic Plastic and Reconstructive Surgery, 2026.Meta-analysis, mostly glaucoma drops
- 27Revisiting the safety of prostaglandin analog eyelash growth productsSteinsapir and Steinsapir. Dermatologic Surgery, 2021.Independent review
- 28Prostaglandin analogues in cosmetic products formulated for eyelash lengtheningCouteau and Coiffard. Annales Pharmaceutiques Françaises, 2026.Label survey: 79 products
- 29FDA seizes eyelash growth product containing bimatoprostHealio Ophthalmology, quoting the FDA. 2007.News report of an official action
- 30Cosmetic Ingredient Hotlist: prohibited and restricted ingredientsHealth Canada. Government of Canada.Regulator
- 31Recalls: prostaglandin analogues in lash conditioners (2014); EyEnvy conditioner (2022)Health Canada. Recalls and safety alerts.Regulator
- 32Opinion on prostaglandins and prostaglandin-analogues used in cosmetic productsEuropean Commission, Scientific Committee on Consumer Safety. SCCS/1635/21, 2022.Official safety opinion
- 33Opinion on prostaglandin analogues used in cosmetic productsEuropean Commission, Scientific Committee on Consumer Safety. SCCS/1680/25, February 2026.Official safety opinion
- 34Effect of a prostaglandin analog-based eyelash serum on tear film stability and the ocular surfaceSánchez González, Gandullo-Asuar, Ballesteros Sánchez and colleagues. Eye and Contact Lens, 2026.One study: 19 women, no control group
- 35Open clinical trial evaluating the efficacy of a novel eyelash growth enhancer with peptides and glycosaminoglycansFernandez-Gonzalez, Truchuelo-Díez and Gómez-Sánchez. Journal of Cosmetic Dermatology, 2024.Open study: 30 women, no comparison group
- 36An open-label, single-center, safety and efficacy study of eyelash polygrowth factor serumSachdev, Velugotla, Revanker and Somasekhar. Journal of Clinical and Aesthetic Dermatology, 2020.Open study: 29 women, no comparison group
- 37A review of the use of biotin for hair lossPatel, Swink and Castelo-Soccio. Skin Appendage Disorders, 2017.Review of the published research
- 38The role of vitamins and minerals in hair loss: a reviewAlmohanna, Ahmed, Tsatalis and Tosti. Dermatology and Therapy, 2019.Review of the published research
- 39Preseptal cellulitis associated with cosmetic eyelash lifting procedureMangan and Imamoglu. Journal of Cosmetic Dermatology, 2021.Case report
- 40Contact allergy to para-phenylenediamine in a permanent eyelash dyeTeixeira, de Wachter, Ronsyn and Goossens. Contact Dermatitis, 2006.Case report
- 41Ocular argyrosis after long-term self-application of eyelash tintGallardo, Randleman, Price and colleagues. American Journal of Ophthalmology, 2006.Three cases
- 42The role of eyelash dyes in allergic eye diseasesMselle. Tropical Doctor, 2004.Case-control study, mostly homemade dyes
- 43Epidemiologic analysis of change in eyelash characteristics with increasing age in a population of healthy womenGlaser, Jones, Carruthers and colleagues. Dermatologic Surgery, 2014.Measured: 179 women
Lash science
The natural lash
- Anatomy and the growth cycleRead
- Chemistry: keratin, bonds, pigmentRead
- Physics: length, curve, structure, loadRead
- Evolution and functionRead
- Psychology and the perception of beautyRead
- Health: keeping and improving natural lashesThis chapter